what case study means

The Ultimate Guide to Qualitative Research - Part 1: The Basics

• Introduction and overview
• What is qualitative research?
• What is qualitative data?
• Examples of qualitative data
• Qualitative vs. quantitative research
• Mixed methods
• Qualitative research preparation
• Theoretical perspective
• Theoretical framework
• Literature reviews

Research question

• Conceptual framework
• Conceptual vs. theoretical framework

Data collection

• Qualitative research methods
• Focus groups
• Observational research

What is a case study?

Applications for case study research, what is a good case study, process of case study design, benefits and limitations of case studies.

• Ethnographical research
• Ethical considerations
• Confidentiality and privacy
• Power dynamics
• Reflexivity

Case studies

Case studies are essential to qualitative research , offering a lens through which researchers can investigate complex phenomena within their real-life contexts. This chapter explores the concept, purpose, applications, examples, and types of case studies and provides guidance on how to conduct case study research effectively.

Whereas quantitative methods look at phenomena at scale, case study research looks at a concept or phenomenon in considerable detail. While analyzing a single case can help understand one perspective regarding the object of research inquiry, analyzing multiple cases can help obtain a more holistic sense of the topic or issue. Let's provide a basic definition of a case study, then explore its characteristics and role in the qualitative research process.

Definition of a case study

A case study in qualitative research is a strategy of inquiry that involves an in-depth investigation of a phenomenon within its real-world context. It provides researchers with the opportunity to acquire an in-depth understanding of intricate details that might not be as apparent or accessible through other methods of research. The specific case or cases being studied can be a single person, group, or organization – demarcating what constitutes a relevant case worth studying depends on the researcher and their research question .

Among qualitative research methods , a case study relies on multiple sources of evidence, such as documents, artifacts, interviews , or observations , to present a complete and nuanced understanding of the phenomenon under investigation. The objective is to illuminate the readers' understanding of the phenomenon beyond its abstract statistical or theoretical explanations.

Characteristics of case studies

Case studies typically possess a number of distinct characteristics that set them apart from other research methods. These characteristics include a focus on holistic description and explanation, flexibility in the design and data collection methods, reliance on multiple sources of evidence, and emphasis on the context in which the phenomenon occurs.

Furthermore, case studies can often involve a longitudinal examination of the case, meaning they study the case over a period of time. These characteristics allow case studies to yield comprehensive, in-depth, and richly contextualized insights about the phenomenon of interest.

The role of case studies in research

Case studies hold a unique position in the broader landscape of research methods aimed at theory development. They are instrumental when the primary research interest is to gain an intensive, detailed understanding of a phenomenon in its real-life context.

In addition, case studies can serve different purposes within research - they can be used for exploratory, descriptive, or explanatory purposes, depending on the research question and objectives. This flexibility and depth make case studies a valuable tool in the toolkit of qualitative researchers.

Remember, a well-conducted case study can offer a rich, insightful contribution to both academic and practical knowledge through theory development or theory verification, thus enhancing our understanding of complex phenomena in their real-world contexts.

What is the purpose of a case study?

Case study research aims for a more comprehensive understanding of phenomena, requiring various research methods to gather information for qualitative analysis . Ultimately, a case study can allow the researcher to gain insight into a particular object of inquiry and develop a theoretical framework relevant to the research inquiry.

Why use case studies in qualitative research?

Using case studies as a research strategy depends mainly on the nature of the research question and the researcher's access to the data.

Conducting case study research provides a level of detail and contextual richness that other research methods might not offer. They are beneficial when there's a need to understand complex social phenomena within their natural contexts.

The explanatory, exploratory, and descriptive roles of case studies

Case studies can take on various roles depending on the research objectives. They can be exploratory when the research aims to discover new phenomena or define new research questions; they are descriptive when the objective is to depict a phenomenon within its context in a detailed manner; and they can be explanatory if the goal is to understand specific relationships within the studied context. Thus, the versatility of case studies allows researchers to approach their topic from different angles, offering multiple ways to uncover and interpret the data .

The impact of case studies on knowledge development

Case studies play a significant role in knowledge development across various disciplines. Analysis of cases provides an avenue for researchers to explore phenomena within their context based on the collected data.

This can result in the production of rich, practical insights that can be instrumental in both theory-building and practice. Case studies allow researchers to delve into the intricacies and complexities of real-life situations, uncovering insights that might otherwise remain hidden.

Types of case studies

In qualitative research , a case study is not a one-size-fits-all approach. Depending on the nature of the research question and the specific objectives of the study, researchers might choose to use different types of case studies. These types differ in their focus, methodology, and the level of detail they provide about the phenomenon under investigation.

Understanding these types is crucial for selecting the most appropriate approach for your research project and effectively achieving your research goals. Let's briefly look at the main types of case studies.

Exploratory case studies

Exploratory case studies are typically conducted to develop a theory or framework around an understudied phenomenon. They can also serve as a precursor to a larger-scale research project. Exploratory case studies are useful when a researcher wants to identify the key issues or questions which can spur more extensive study or be used to develop propositions for further research. These case studies are characterized by flexibility, allowing researchers to explore various aspects of a phenomenon as they emerge, which can also form the foundation for subsequent studies.

Descriptive case studies

Descriptive case studies aim to provide a complete and accurate representation of a phenomenon or event within its context. These case studies are often based on an established theoretical framework, which guides how data is collected and analyzed. The researcher is concerned with describing the phenomenon in detail, as it occurs naturally, without trying to influence or manipulate it.

Explanatory case studies

Explanatory case studies are focused on explanation - they seek to clarify how or why certain phenomena occur. Often used in complex, real-life situations, they can be particularly valuable in clarifying causal relationships among concepts and understanding the interplay between different factors within a specific context.

Intrinsic, instrumental, and collective case studies

These three categories of case studies focus on the nature and purpose of the study. An intrinsic case study is conducted when a researcher has an inherent interest in the case itself. Instrumental case studies are employed when the case is used to provide insight into a particular issue or phenomenon. A collective case study, on the other hand, involves studying multiple cases simultaneously to investigate some general phenomena.

Each type of case study serves a different purpose and has its own strengths and challenges. The selection of the type should be guided by the research question and objectives, as well as the context and constraints of the research.

The flexibility, depth, and contextual richness offered by case studies make this approach an excellent research method for various fields of study. They enable researchers to investigate real-world phenomena within their specific contexts, capturing nuances that other research methods might miss. Across numerous fields, case studies provide valuable insights into complex issues.

Critical information systems research

Case studies provide a detailed understanding of the role and impact of information systems in different contexts. They offer a platform to explore how information systems are designed, implemented, and used and how they interact with various social, economic, and political factors. Case studies in this field often focus on examining the intricate relationship between technology, organizational processes, and user behavior, helping to uncover insights that can inform better system design and implementation.

Health research

Health research is another field where case studies are highly valuable. They offer a way to explore patient experiences, healthcare delivery processes, and the impact of various interventions in a real-world context.

Case studies can provide a deep understanding of a patient's journey, giving insights into the intricacies of disease progression, treatment effects, and the psychosocial aspects of health and illness.

Asthma research studies

Specifically within medical research, studies on asthma often employ case studies to explore the individual and environmental factors that influence asthma development, management, and outcomes. A case study can provide rich, detailed data about individual patients' experiences, from the triggers and symptoms they experience to the effectiveness of various management strategies. This can be crucial for developing patient-centered asthma care approaches.

Other fields

Apart from the fields mentioned, case studies are also extensively used in business and management research, education research, and political sciences, among many others. They provide an opportunity to delve into the intricacies of real-world situations, allowing for a comprehensive understanding of various phenomena.

Case studies, with their depth and contextual focus, offer unique insights across these varied fields. They allow researchers to illuminate the complexities of real-life situations, contributing to both theory and practice.

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Understanding the key elements of case study design is crucial for conducting rigorous and impactful case study research. A well-structured design guides the researcher through the process, ensuring that the study is methodologically sound and its findings are reliable and valid. The main elements of case study design include the research question , propositions, units of analysis, and the logic linking the data to the propositions.

The research question is the foundation of any research study. A good research question guides the direction of the study and informs the selection of the case, the methods of collecting data, and the analysis techniques. A well-formulated research question in case study research is typically clear, focused, and complex enough to merit further detailed examination of the relevant case(s).

Propositions

Propositions, though not necessary in every case study, provide a direction by stating what we might expect to find in the data collected. They guide how data is collected and analyzed by helping researchers focus on specific aspects of the case. They are particularly important in explanatory case studies, which seek to understand the relationships among concepts within the studied phenomenon.

Units of analysis

The unit of analysis refers to the case, or the main entity or entities that are being analyzed in the study. In case study research, the unit of analysis can be an individual, a group, an organization, a decision, an event, or even a time period. It's crucial to clearly define the unit of analysis, as it shapes the qualitative data analysis process by allowing the researcher to analyze a particular case and synthesize analysis across multiple case studies to draw conclusions.

Argumentation

This refers to the inferential model that allows researchers to draw conclusions from the data. The researcher needs to ensure that there is a clear link between the data, the propositions (if any), and the conclusions drawn. This argumentation is what enables the researcher to make valid and credible inferences about the phenomenon under study.

Understanding and carefully considering these elements in the design phase of a case study can significantly enhance the quality of the research. It can help ensure that the study is methodologically sound and its findings contribute meaningful insights about the case.

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Conducting a case study involves several steps, from defining the research question and selecting the case to collecting and analyzing data . This section outlines these key stages, providing a practical guide on how to conduct case study research.

Defining the research question

The first step in case study research is defining a clear, focused research question. This question should guide the entire research process, from case selection to analysis. It's crucial to ensure that the research question is suitable for a case study approach. Typically, such questions are exploratory or descriptive in nature and focus on understanding a phenomenon within its real-life context.

Selecting and defining the case

The selection of the case should be based on the research question and the objectives of the study. It involves choosing a unique example or a set of examples that provide rich, in-depth data about the phenomenon under investigation. After selecting the case, it's crucial to define it clearly, setting the boundaries of the case, including the time period and the specific context.

Previous research can help guide the case study design. When considering a case study, an example of a case could be taken from previous case study research and used to define cases in a new research inquiry. Considering recently published examples can help understand how to select and define cases effectively.

Developing a detailed case study protocol

A case study protocol outlines the procedures and general rules to be followed during the case study. This includes the data collection methods to be used, the sources of data, and the procedures for analysis. Having a detailed case study protocol ensures consistency and reliability in the study.

The protocol should also consider how to work with the people involved in the research context to grant the research team access to collecting data. As mentioned in previous sections of this guide, establishing rapport is an essential component of qualitative research as it shapes the overall potential for collecting and analyzing data.

Collecting data

Gathering data in case study research often involves multiple sources of evidence, including documents, archival records, interviews, observations, and physical artifacts. This allows for a comprehensive understanding of the case. The process for gathering data should be systematic and carefully documented to ensure the reliability and validity of the study.

Analyzing and interpreting data

The next step is analyzing the data. This involves organizing the data , categorizing it into themes or patterns , and interpreting these patterns to answer the research question. The analysis might also involve comparing the findings with prior research or theoretical propositions.

Writing the case study report

The final step is writing the case study report . This should provide a detailed description of the case, the data, the analysis process, and the findings. The report should be clear, organized, and carefully written to ensure that the reader can understand the case and the conclusions drawn from it.

Each of these steps is crucial in ensuring that the case study research is rigorous, reliable, and provides valuable insights about the case.

The type, depth, and quality of data in your study can significantly influence the validity and utility of the study. In case study research, data is usually collected from multiple sources to provide a comprehensive and nuanced understanding of the case. This section will outline the various methods of collecting data used in case study research and discuss considerations for ensuring the quality of the data.

Interviews are a common method of gathering data in case study research. They can provide rich, in-depth data about the perspectives, experiences, and interpretations of the individuals involved in the case. Interviews can be structured , semi-structured , or unstructured , depending on the research question and the degree of flexibility needed.

Observations

Observations involve the researcher observing the case in its natural setting, providing first-hand information about the case and its context. Observations can provide data that might not be revealed in interviews or documents, such as non-verbal cues or contextual information.

Documents and artifacts

Documents and archival records provide a valuable source of data in case study research. They can include reports, letters, memos, meeting minutes, email correspondence, and various public and private documents related to the case.

These records can provide historical context, corroborate evidence from other sources, and offer insights into the case that might not be apparent from interviews or observations.

Physical artifacts refer to any physical evidence related to the case, such as tools, products, or physical environments. These artifacts can provide tangible insights into the case, complementing the data gathered from other sources.

Ensuring the quality of data collection

Determining the quality of data in case study research requires careful planning and execution. It's crucial to ensure that the data is reliable, accurate, and relevant to the research question. This involves selecting appropriate methods of collecting data, properly training interviewers or observers, and systematically recording and storing the data. It also includes considering ethical issues related to collecting and handling data, such as obtaining informed consent and ensuring the privacy and confidentiality of the participants.

Data analysis

Analyzing case study research involves making sense of the rich, detailed data to answer the research question. This process can be challenging due to the volume and complexity of case study data. However, a systematic and rigorous approach to analysis can ensure that the findings are credible and meaningful. This section outlines the main steps and considerations in analyzing data in case study research.

Organizing the data

The first step in the analysis is organizing the data. This involves sorting the data into manageable sections, often according to the data source or the theme. This step can also involve transcribing interviews, digitizing physical artifacts, or organizing observational data.

Categorizing and coding the data

Once the data is organized, the next step is to categorize or code the data. This involves identifying common themes, patterns, or concepts in the data and assigning codes to relevant data segments. Coding can be done manually or with the help of software tools, and in either case, qualitative analysis software can greatly facilitate the entire coding process. Coding helps to reduce the data to a set of themes or categories that can be more easily analyzed.

Identifying patterns and themes

After coding the data, the researcher looks for patterns or themes in the coded data. This involves comparing and contrasting the codes and looking for relationships or patterns among them. The identified patterns and themes should help answer the research question.

Interpreting the data

Once patterns and themes have been identified, the next step is to interpret these findings. This involves explaining what the patterns or themes mean in the context of the research question and the case. This interpretation should be grounded in the data, but it can also involve drawing on theoretical concepts or prior research.

Verification of the data

The last step in the analysis is verification. This involves checking the accuracy and consistency of the analysis process and confirming that the findings are supported by the data. This can involve re-checking the original data, checking the consistency of codes, or seeking feedback from research participants or peers.

Like any research method , case study research has its strengths and limitations. Researchers must be aware of these, as they can influence the design, conduct, and interpretation of the study.

Understanding the strengths and limitations of case study research can also guide researchers in deciding whether this approach is suitable for their research question . This section outlines some of the key strengths and limitations of case study research.

Benefits include the following:

• Rich, detailed data: One of the main strengths of case study research is that it can generate rich, detailed data about the case. This can provide a deep understanding of the case and its context, which can be valuable in exploring complex phenomena.
• Flexibility: Case study research is flexible in terms of design , data collection , and analysis . A sufficient degree of flexibility allows the researcher to adapt the study according to the case and the emerging findings.
• Real-world context: Case study research involves studying the case in its real-world context, which can provide valuable insights into the interplay between the case and its context.
• Multiple sources of evidence: Case study research often involves collecting data from multiple sources , which can enhance the robustness and validity of the findings.

On the other hand, researchers should consider the following limitations:

• Generalizability: A common criticism of case study research is that its findings might not be generalizable to other cases due to the specificity and uniqueness of each case.
• Time and resource intensive: Case study research can be time and resource intensive due to the depth of the investigation and the amount of collected data.
• Complexity of analysis: The rich, detailed data generated in case study research can make analyzing the data challenging.
• Subjectivity: Given the nature of case study research, there may be a higher degree of subjectivity in interpreting the data , so researchers need to reflect on this and transparently convey to audiences how the research was conducted.

Being aware of these strengths and limitations can help researchers design and conduct case study research effectively and interpret and report the findings appropriately.

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What Is a Case Study?

Weighing the pros and cons of this method of research

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Cara Lustik is a fact-checker and copywriter.

Verywell / Colleen Tighe

• Pros and Cons

What Types of Case Studies Are Out There?

Where do you find data for a case study, how do i write a psychology case study.

A case study is an in-depth study of one person, group, or event. In a case study, nearly every aspect of the subject's life and history is analyzed to seek patterns and causes of behavior. Case studies can be used in many different fields, including psychology, medicine, education, anthropology, political science, and social work.

The point of a case study is to learn as much as possible about an individual or group so that the information can be generalized to many others. Unfortunately, case studies tend to be highly subjective, and it is sometimes difficult to generalize results to a larger population.

While case studies focus on a single individual or group, they follow a format similar to other types of psychology writing. If you are writing a case study, we got you—here are some rules of APA format to reference.  

At a Glance

A case study, or an in-depth study of a person, group, or event, can be a useful research tool when used wisely. In many cases, case studies are best used in situations where it would be difficult or impossible for you to conduct an experiment. They are helpful for looking at unique situations and allow researchers to gather a lot of˜ information about a specific individual or group of people. However, it's important to be cautious of any bias we draw from them as they are highly subjective.

What Are the Benefits and Limitations of Case Studies?

A case study can have its strengths and weaknesses. Researchers must consider these pros and cons before deciding if this type of study is appropriate for their needs.

One of the greatest advantages of a case study is that it allows researchers to investigate things that are often difficult or impossible to replicate in a lab. Some other benefits of a case study:

• Allows researchers to capture information on the 'how,' 'what,' and 'why,' of something that's implemented
• Gives researchers the chance to collect information on why one strategy might be chosen over another
• Permits researchers to develop hypotheses that can be explored in experimental research

On the other hand, a case study can have some drawbacks:

• It cannot necessarily be generalized to the larger population
• Cannot demonstrate cause and effect
• It may not be scientifically rigorous
• It can lead to bias

Researchers may choose to perform a case study if they want to explore a unique or recently discovered phenomenon. Through their insights, researchers develop additional ideas and study questions that might be explored in future studies.

It's important to remember that the insights from case studies cannot be used to determine cause-and-effect relationships between variables. However, case studies may be used to develop hypotheses that can then be addressed in experimental research.

Case Study Examples

There have been a number of notable case studies in the history of psychology. Much of  Freud's work and theories were developed through individual case studies. Some great examples of case studies in psychology include:

• Anna O : Anna O. was a pseudonym of a woman named Bertha Pappenheim, a patient of a physician named Josef Breuer. While she was never a patient of Freud's, Freud and Breuer discussed her case extensively. The woman was experiencing symptoms of a condition that was then known as hysteria and found that talking about her problems helped relieve her symptoms. Her case played an important part in the development of talk therapy as an approach to mental health treatment.
• Phineas Gage : Phineas Gage was a railroad employee who experienced a terrible accident in which an explosion sent a metal rod through his skull, damaging important portions of his brain. Gage recovered from his accident but was left with serious changes in both personality and behavior.
• Genie : Genie was a young girl subjected to horrific abuse and isolation. The case study of Genie allowed researchers to study whether language learning was possible, even after missing critical periods for language development. Her case also served as an example of how scientific research may interfere with treatment and lead to further abuse of vulnerable individuals.

Such cases demonstrate how case research can be used to study things that researchers could not replicate in experimental settings. In Genie's case, her horrific abuse denied her the opportunity to learn a language at critical points in her development.

This is clearly not something researchers could ethically replicate, but conducting a case study on Genie allowed researchers to study phenomena that are otherwise impossible to reproduce.

There are a few different types of case studies that psychologists and other researchers might use:

• Collective case studies : These involve studying a group of individuals. Researchers might study a group of people in a certain setting or look at an entire community. For example, psychologists might explore how access to resources in a community has affected the collective mental well-being of those who live there.
• Descriptive case studies : These involve starting with a descriptive theory. The subjects are then observed, and the information gathered is compared to the pre-existing theory.
• Explanatory case studies : These   are often used to do causal investigations. In other words, researchers are interested in looking at factors that may have caused certain things to occur.
• Exploratory case studies : These are sometimes used as a prelude to further, more in-depth research. This allows researchers to gather more information before developing their research questions and hypotheses .
• Instrumental case studies : These occur when the individual or group allows researchers to understand more than what is initially obvious to observers.
• Intrinsic case studies : This type of case study is when the researcher has a personal interest in the case. Jean Piaget's observations of his own children are good examples of how an intrinsic case study can contribute to the development of a psychological theory.

The three main case study types often used are intrinsic, instrumental, and collective. Intrinsic case studies are useful for learning about unique cases. Instrumental case studies help look at an individual to learn more about a broader issue. A collective case study can be useful for looking at several cases simultaneously.

The type of case study that psychology researchers use depends on the unique characteristics of the situation and the case itself.

There are a number of different sources and methods that researchers can use to gather information about an individual or group. Six major sources that have been identified by researchers are:

• Archival records : Census records, survey records, and name lists are examples of archival records.
• Direct observation : This strategy involves observing the subject, often in a natural setting . While an individual observer is sometimes used, it is more common to utilize a group of observers.
• Documents : Letters, newspaper articles, administrative records, etc., are the types of documents often used as sources.
• Interviews : Interviews are one of the most important methods for gathering information in case studies. An interview can involve structured survey questions or more open-ended questions.
• Participant observation : When the researcher serves as a participant in events and observes the actions and outcomes, it is called participant observation.
• Physical artifacts : Tools, objects, instruments, and other artifacts are often observed during a direct observation of the subject.

If you have been directed to write a case study for a psychology course, be sure to check with your instructor for any specific guidelines you need to follow. If you are writing your case study for a professional publication, check with the publisher for their specific guidelines for submitting a case study.

Here is a general outline of what should be included in a case study.

Section 1: A Case History

This section will have the following structure and content:

Background information : The first section of your paper will present your client's background. Include factors such as age, gender, work, health status, family mental health history, family and social relationships, drug and alcohol history, life difficulties, goals, and coping skills and weaknesses.

Description of the presenting problem : In the next section of your case study, you will describe the problem or symptoms that the client presented with.

Describe any physical, emotional, or sensory symptoms reported by the client. Thoughts, feelings, and perceptions related to the symptoms should also be noted. Any screening or diagnostic assessments that are used should also be described in detail and all scores reported.

Your diagnosis : Provide your diagnosis and give the appropriate Diagnostic and Statistical Manual code. Explain how you reached your diagnosis, how the client's symptoms fit the diagnostic criteria for the disorder(s), or any possible difficulties in reaching a diagnosis.

Section 2: Treatment Plan

This portion of the paper will address the chosen treatment for the condition. This might also include the theoretical basis for the chosen treatment or any other evidence that might exist to support why this approach was chosen.

• Cognitive behavioral approach : Explain how a cognitive behavioral therapist would approach treatment. Offer background information on cognitive behavioral therapy and describe the treatment sessions, client response, and outcome of this type of treatment. Make note of any difficulties or successes encountered by your client during treatment.
• Humanistic approach : Describe a humanistic approach that could be used to treat your client, such as client-centered therapy . Provide information on the type of treatment you chose, the client's reaction to the treatment, and the end result of this approach. Explain why the treatment was successful or unsuccessful.
• Psychoanalytic approach : Describe how a psychoanalytic therapist would view the client's problem. Provide some background on the psychoanalytic approach and cite relevant references. Explain how psychoanalytic therapy would be used to treat the client, how the client would respond to therapy, and the effectiveness of this treatment approach.
• Pharmacological approach : If treatment primarily involves the use of medications, explain which medications were used and why. Provide background on the effectiveness of these medications and how monotherapy may compare with an approach that combines medications with therapy or other treatments.

This section of a case study should also include information about the treatment goals, process, and outcomes.

When you are writing a case study, you should also include a section where you discuss the case study itself, including the strengths and limitiations of the study. You should note how the findings of your case study might support previous research. 

In your discussion section, you should also describe some of the implications of your case study. What ideas or findings might require further exploration? How might researchers go about exploring some of these questions in additional studies?

Need More Tips?

Here are a few additional pointers to keep in mind when formatting your case study:

• Never refer to the subject of your case study as "the client." Instead, use their name or a pseudonym.
• Read examples of case studies to gain an idea about the style and format.
• Remember to use APA format when citing references .

Crowe S, Cresswell K, Robertson A, Huby G, Avery A, Sheikh A. The case study approach .  BMC Med Res Methodol . 2011;11:100.

Crowe S, Cresswell K, Robertson A, Huby G, Avery A, Sheikh A. The case study approach . BMC Med Res Methodol . 2011 Jun 27;11:100. doi:10.1186/1471-2288-11-100

Gagnon, Yves-Chantal.  The Case Study as Research Method: A Practical Handbook . Canada, Chicago Review Press Incorporated DBA Independent Pub Group, 2010.

Yin, Robert K. Case Study Research and Applications: Design and Methods . United States, SAGE Publications, 2017.

By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

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• Case Study | Definition, Examples & Methods

Case Study | Definition, Examples & Methods

Published on 5 May 2022 by Shona McCombes . Revised on 30 January 2023.

A case study is a detailed study of a specific subject, such as a person, group, place, event, organisation, or phenomenon. Case studies are commonly used in social, educational, clinical, and business research.

A case study research design usually involves qualitative methods , but quantitative methods are sometimes also used. Case studies are good for describing , comparing, evaluating, and understanding different aspects of a research problem .

Table of contents

When to do a case study, step 1: select a case, step 2: build a theoretical framework, step 3: collect your data, step 4: describe and analyse the case.

A case study is an appropriate research design when you want to gain concrete, contextual, in-depth knowledge about a specific real-world subject. It allows you to explore the key characteristics, meanings, and implications of the case.

Case studies are often a good choice in a thesis or dissertation . They keep your project focused and manageable when you don’t have the time or resources to do large-scale research.

You might use just one complex case study where you explore a single subject in depth, or conduct multiple case studies to compare and illuminate different aspects of your research problem.

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Once you have developed your problem statement and research questions , you should be ready to choose the specific case that you want to focus on. A good case study should have the potential to:

• Provide new or unexpected insights into the subject
• Challenge or complicate existing assumptions and theories
• Propose practical courses of action to resolve a problem
• Open up new directions for future research

Unlike quantitative or experimental research, a strong case study does not require a random or representative sample. In fact, case studies often deliberately focus on unusual, neglected, or outlying cases which may shed new light on the research problem.

If you find yourself aiming to simultaneously investigate and solve an issue, consider conducting action research . As its name suggests, action research conducts research and takes action at the same time, and is highly iterative and flexible. 

However, you can also choose a more common or representative case to exemplify a particular category, experience, or phenomenon.

While case studies focus more on concrete details than general theories, they should usually have some connection with theory in the field. This way the case study is not just an isolated description, but is integrated into existing knowledge about the topic. It might aim to:

• Exemplify a theory by showing how it explains the case under investigation
• Expand on a theory by uncovering new concepts and ideas that need to be incorporated
• Challenge a theory by exploring an outlier case that doesn’t fit with established assumptions

To ensure that your analysis of the case has a solid academic grounding, you should conduct a literature review of sources related to the topic and develop a theoretical framework . This means identifying key concepts and theories to guide your analysis and interpretation.

There are many different research methods you can use to collect data on your subject. Case studies tend to focus on qualitative data using methods such as interviews, observations, and analysis of primary and secondary sources (e.g., newspaper articles, photographs, official records). Sometimes a case study will also collect quantitative data .

The aim is to gain as thorough an understanding as possible of the case and its context.

In writing up the case study, you need to bring together all the relevant aspects to give as complete a picture as possible of the subject.

How you report your findings depends on the type of research you are doing. Some case studies are structured like a standard scientific paper or thesis, with separate sections or chapters for the methods , results , and discussion .

Others are written in a more narrative style, aiming to explore the case from various angles and analyse its meanings and implications (for example, by using textual analysis or discourse analysis ).

In all cases, though, make sure to give contextual details about the case, connect it back to the literature and theory, and discuss how it fits into wider patterns or debates.

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1914, in the meaning defined at sense 1

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Home » Case Study – Methods, Examples and Guide

Case Study – Methods, Examples and Guide

Table of Contents

A case study is a research method that involves an in-depth examination and analysis of a particular phenomenon or case, such as an individual, organization, community, event, or situation.

It is a qualitative research approach that aims to provide a detailed and comprehensive understanding of the case being studied. Case studies typically involve multiple sources of data, including interviews, observations, documents, and artifacts, which are analyzed using various techniques, such as content analysis, thematic analysis, and grounded theory. The findings of a case study are often used to develop theories, inform policy or practice, or generate new research questions.

Types of Case Study

Types and Methods of Case Study are as follows:

Single-Case Study

A single-case study is an in-depth analysis of a single case. This type of case study is useful when the researcher wants to understand a specific phenomenon in detail.

For Example , A researcher might conduct a single-case study on a particular individual to understand their experiences with a particular health condition or a specific organization to explore their management practices. The researcher collects data from multiple sources, such as interviews, observations, and documents, and uses various techniques to analyze the data, such as content analysis or thematic analysis. The findings of a single-case study are often used to generate new research questions, develop theories, or inform policy or practice.

Multiple-Case Study

A multiple-case study involves the analysis of several cases that are similar in nature. This type of case study is useful when the researcher wants to identify similarities and differences between the cases.

For Example, a researcher might conduct a multiple-case study on several companies to explore the factors that contribute to their success or failure. The researcher collects data from each case, compares and contrasts the findings, and uses various techniques to analyze the data, such as comparative analysis or pattern-matching. The findings of a multiple-case study can be used to develop theories, inform policy or practice, or generate new research questions.

Exploratory Case Study

An exploratory case study is used to explore a new or understudied phenomenon. This type of case study is useful when the researcher wants to generate hypotheses or theories about the phenomenon.

For Example, a researcher might conduct an exploratory case study on a new technology to understand its potential impact on society. The researcher collects data from multiple sources, such as interviews, observations, and documents, and uses various techniques to analyze the data, such as grounded theory or content analysis. The findings of an exploratory case study can be used to generate new research questions, develop theories, or inform policy or practice.

Descriptive Case Study

A descriptive case study is used to describe a particular phenomenon in detail. This type of case study is useful when the researcher wants to provide a comprehensive account of the phenomenon.

For Example, a researcher might conduct a descriptive case study on a particular community to understand its social and economic characteristics. The researcher collects data from multiple sources, such as interviews, observations, and documents, and uses various techniques to analyze the data, such as content analysis or thematic analysis. The findings of a descriptive case study can be used to inform policy or practice or generate new research questions.

Instrumental Case Study

An instrumental case study is used to understand a particular phenomenon that is instrumental in achieving a particular goal. This type of case study is useful when the researcher wants to understand the role of the phenomenon in achieving the goal.

For Example, a researcher might conduct an instrumental case study on a particular policy to understand its impact on achieving a particular goal, such as reducing poverty. The researcher collects data from multiple sources, such as interviews, observations, and documents, and uses various techniques to analyze the data, such as content analysis or thematic analysis. The findings of an instrumental case study can be used to inform policy or practice or generate new research questions.

Case Study Data Collection Methods

Here are some common data collection methods for case studies:

Interviews involve asking questions to individuals who have knowledge or experience relevant to the case study. Interviews can be structured (where the same questions are asked to all participants) or unstructured (where the interviewer follows up on the responses with further questions). Interviews can be conducted in person, over the phone, or through video conferencing.

Observations

Observations involve watching and recording the behavior and activities of individuals or groups relevant to the case study. Observations can be participant (where the researcher actively participates in the activities) or non-participant (where the researcher observes from a distance). Observations can be recorded using notes, audio or video recordings, or photographs.

Documents can be used as a source of information for case studies. Documents can include reports, memos, emails, letters, and other written materials related to the case study. Documents can be collected from the case study participants or from public sources.

Surveys involve asking a set of questions to a sample of individuals relevant to the case study. Surveys can be administered in person, over the phone, through mail or email, or online. Surveys can be used to gather information on attitudes, opinions, or behaviors related to the case study.

Artifacts are physical objects relevant to the case study. Artifacts can include tools, equipment, products, or other objects that provide insights into the case study phenomenon.

How to conduct Case Study Research

Conducting a case study research involves several steps that need to be followed to ensure the quality and rigor of the study. Here are the steps to conduct case study research:

• Define the research questions: The first step in conducting a case study research is to define the research questions. The research questions should be specific, measurable, and relevant to the case study phenomenon under investigation.
• Select the case: The next step is to select the case or cases to be studied. The case should be relevant to the research questions and should provide rich and diverse data that can be used to answer the research questions.
• Collect data: Data can be collected using various methods, such as interviews, observations, documents, surveys, and artifacts. The data collection method should be selected based on the research questions and the nature of the case study phenomenon.
• Analyze the data: The data collected from the case study should be analyzed using various techniques, such as content analysis, thematic analysis, or grounded theory. The analysis should be guided by the research questions and should aim to provide insights and conclusions relevant to the research questions.
• Draw conclusions: The conclusions drawn from the case study should be based on the data analysis and should be relevant to the research questions. The conclusions should be supported by evidence and should be clearly stated.
• Validate the findings: The findings of the case study should be validated by reviewing the data and the analysis with participants or other experts in the field. This helps to ensure the validity and reliability of the findings.
• Write the report: The final step is to write the report of the case study research. The report should provide a clear description of the case study phenomenon, the research questions, the data collection methods, the data analysis, the findings, and the conclusions. The report should be written in a clear and concise manner and should follow the guidelines for academic writing.

Examples of Case Study

Here are some examples of case study research:

• The Hawthorne Studies : Conducted between 1924 and 1932, the Hawthorne Studies were a series of case studies conducted by Elton Mayo and his colleagues to examine the impact of work environment on employee productivity. The studies were conducted at the Hawthorne Works plant of the Western Electric Company in Chicago and included interviews, observations, and experiments.
• The Stanford Prison Experiment: Conducted in 1971, the Stanford Prison Experiment was a case study conducted by Philip Zimbardo to examine the psychological effects of power and authority. The study involved simulating a prison environment and assigning participants to the role of guards or prisoners. The study was controversial due to the ethical issues it raised.
• The Challenger Disaster: The Challenger Disaster was a case study conducted to examine the causes of the Space Shuttle Challenger explosion in 1986. The study included interviews, observations, and analysis of data to identify the technical, organizational, and cultural factors that contributed to the disaster.
• The Enron Scandal: The Enron Scandal was a case study conducted to examine the causes of the Enron Corporation’s bankruptcy in 2001. The study included interviews, analysis of financial data, and review of documents to identify the accounting practices, corporate culture, and ethical issues that led to the company’s downfall.
• The Fukushima Nuclear Disaster : The Fukushima Nuclear Disaster was a case study conducted to examine the causes of the nuclear accident that occurred at the Fukushima Daiichi Nuclear Power Plant in Japan in 2011. The study included interviews, analysis of data, and review of documents to identify the technical, organizational, and cultural factors that contributed to the disaster.

Application of Case Study

Case studies have a wide range of applications across various fields and industries. Here are some examples:

Business and Management

Case studies are widely used in business and management to examine real-life situations and develop problem-solving skills. Case studies can help students and professionals to develop a deep understanding of business concepts, theories, and best practices.

Case studies are used in healthcare to examine patient care, treatment options, and outcomes. Case studies can help healthcare professionals to develop critical thinking skills, diagnose complex medical conditions, and develop effective treatment plans.

Case studies are used in education to examine teaching and learning practices. Case studies can help educators to develop effective teaching strategies, evaluate student progress, and identify areas for improvement.

Social Sciences

Case studies are widely used in social sciences to examine human behavior, social phenomena, and cultural practices. Case studies can help researchers to develop theories, test hypotheses, and gain insights into complex social issues.

Law and Ethics

Case studies are used in law and ethics to examine legal and ethical dilemmas. Case studies can help lawyers, policymakers, and ethical professionals to develop critical thinking skills, analyze complex cases, and make informed decisions.

Purpose of Case Study

The purpose of a case study is to provide a detailed analysis of a specific phenomenon, issue, or problem in its real-life context. A case study is a qualitative research method that involves the in-depth exploration and analysis of a particular case, which can be an individual, group, organization, event, or community.

The primary purpose of a case study is to generate a comprehensive and nuanced understanding of the case, including its history, context, and dynamics. Case studies can help researchers to identify and examine the underlying factors, processes, and mechanisms that contribute to the case and its outcomes. This can help to develop a more accurate and detailed understanding of the case, which can inform future research, practice, or policy.

Case studies can also serve other purposes, including:

• Illustrating a theory or concept: Case studies can be used to illustrate and explain theoretical concepts and frameworks, providing concrete examples of how they can be applied in real-life situations.
• Developing hypotheses: Case studies can help to generate hypotheses about the causal relationships between different factors and outcomes, which can be tested through further research.
• Providing insight into complex issues: Case studies can provide insights into complex and multifaceted issues, which may be difficult to understand through other research methods.
• Informing practice or policy: Case studies can be used to inform practice or policy by identifying best practices, lessons learned, or areas for improvement.

Advantages of Case Study Research

There are several advantages of case study research, including:

• In-depth exploration: Case study research allows for a detailed exploration and analysis of a specific phenomenon, issue, or problem in its real-life context. This can provide a comprehensive understanding of the case and its dynamics, which may not be possible through other research methods.
• Rich data: Case study research can generate rich and detailed data, including qualitative data such as interviews, observations, and documents. This can provide a nuanced understanding of the case and its complexity.
• Holistic perspective: Case study research allows for a holistic perspective of the case, taking into account the various factors, processes, and mechanisms that contribute to the case and its outcomes. This can help to develop a more accurate and comprehensive understanding of the case.
• Theory development: Case study research can help to develop and refine theories and concepts by providing empirical evidence and concrete examples of how they can be applied in real-life situations.
• Practical application: Case study research can inform practice or policy by identifying best practices, lessons learned, or areas for improvement.
• Contextualization: Case study research takes into account the specific context in which the case is situated, which can help to understand how the case is influenced by the social, cultural, and historical factors of its environment.

Limitations of Case Study Research

There are several limitations of case study research, including:

• Limited generalizability : Case studies are typically focused on a single case or a small number of cases, which limits the generalizability of the findings. The unique characteristics of the case may not be applicable to other contexts or populations, which may limit the external validity of the research.
• Biased sampling: Case studies may rely on purposive or convenience sampling, which can introduce bias into the sample selection process. This may limit the representativeness of the sample and the generalizability of the findings.
• Subjectivity: Case studies rely on the interpretation of the researcher, which can introduce subjectivity into the analysis. The researcher’s own biases, assumptions, and perspectives may influence the findings, which may limit the objectivity of the research.
• Limited control: Case studies are typically conducted in naturalistic settings, which limits the control that the researcher has over the environment and the variables being studied. This may limit the ability to establish causal relationships between variables.
• Time-consuming: Case studies can be time-consuming to conduct, as they typically involve a detailed exploration and analysis of a specific case. This may limit the feasibility of conducting multiple case studies or conducting case studies in a timely manner.
• Resource-intensive: Case studies may require significant resources, including time, funding, and expertise. This may limit the ability of researchers to conduct case studies in resource-constrained settings.

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A case study research paper examines a person, place, event, condition, phenomenon, or other type of subject of analysis in order to extrapolate  key themes and results that help predict future trends, illuminate previously hidden issues that can be applied to practice, and/or provide a means for understanding an important research problem with greater clarity. A case study research paper usually examines a single subject of analysis, but case study papers can also be designed as a comparative investigation that shows relationships between two or more subjects. The methods used to study a case can rest within a quantitative, qualitative, or mixed-method investigative paradigm.

Case Studies. Writing@CSU. Colorado State University; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010 ; “What is a Case Study?” In Swanborn, Peter G. Case Study Research: What, Why and How? London: SAGE, 2010.

How to Approach Writing a Case Study Research Paper

General information about how to choose a topic to investigate can be found under the " Choosing a Research Problem " tab in the Organizing Your Social Sciences Research Paper writing guide. Review this page because it may help you identify a subject of analysis that can be investigated using a case study design.

However, identifying a case to investigate involves more than choosing the research problem . A case study encompasses a problem contextualized around the application of in-depth analysis, interpretation, and discussion, often resulting in specific recommendations for action or for improving existing conditions. As Seawright and Gerring note, practical considerations such as time and access to information can influence case selection, but these issues should not be the sole factors used in describing the methodological justification for identifying a particular case to study. Given this, selecting a case includes considering the following:

• The case represents an unusual or atypical example of a research problem that requires more in-depth analysis? Cases often represent a topic that rests on the fringes of prior investigations because the case may provide new ways of understanding the research problem. For example, if the research problem is to identify strategies to improve policies that support girl's access to secondary education in predominantly Muslim nations, you could consider using Azerbaijan as a case study rather than selecting a more obvious nation in the Middle East. Doing so may reveal important new insights into recommending how governments in other predominantly Muslim nations can formulate policies that support improved access to education for girls.
• The case provides important insight or illuminate a previously hidden problem? In-depth analysis of a case can be based on the hypothesis that the case study will reveal trends or issues that have not been exposed in prior research or will reveal new and important implications for practice. For example, anecdotal evidence may suggest drug use among homeless veterans is related to their patterns of travel throughout the day. Assuming prior studies have not looked at individual travel choices as a way to study access to illicit drug use, a case study that observes a homeless veteran could reveal how issues of personal mobility choices facilitate regular access to illicit drugs. Note that it is important to conduct a thorough literature review to ensure that your assumption about the need to reveal new insights or previously hidden problems is valid and evidence-based.
• The case challenges and offers a counter-point to prevailing assumptions? Over time, research on any given topic can fall into a trap of developing assumptions based on outdated studies that are still applied to new or changing conditions or the idea that something should simply be accepted as "common sense," even though the issue has not been thoroughly tested in current practice. A case study analysis may offer an opportunity to gather evidence that challenges prevailing assumptions about a research problem and provide a new set of recommendations applied to practice that have not been tested previously. For example, perhaps there has been a long practice among scholars to apply a particular theory in explaining the relationship between two subjects of analysis. Your case could challenge this assumption by applying an innovative theoretical framework [perhaps borrowed from another discipline] to explore whether this approach offers new ways of understanding the research problem. Taking a contrarian stance is one of the most important ways that new knowledge and understanding develops from existing literature.
• The case provides an opportunity to pursue action leading to the resolution of a problem? Another way to think about choosing a case to study is to consider how the results from investigating a particular case may result in findings that reveal ways in which to resolve an existing or emerging problem. For example, studying the case of an unforeseen incident, such as a fatal accident at a railroad crossing, can reveal hidden issues that could be applied to preventative measures that contribute to reducing the chance of accidents in the future. In this example, a case study investigating the accident could lead to a better understanding of where to strategically locate additional signals at other railroad crossings so as to better warn drivers of an approaching train, particularly when visibility is hindered by heavy rain, fog, or at night.
• The case offers a new direction in future research? A case study can be used as a tool for an exploratory investigation that highlights the need for further research about the problem. A case can be used when there are few studies that help predict an outcome or that establish a clear understanding about how best to proceed in addressing a problem. For example, after conducting a thorough literature review [very important!], you discover that little research exists showing the ways in which women contribute to promoting water conservation in rural communities of east central Africa. A case study of how women contribute to saving water in a rural village of Uganda can lay the foundation for understanding the need for more thorough research that documents how women in their roles as cooks and family caregivers think about water as a valuable resource within their community. This example of a case study could also point to the need for scholars to build new theoretical frameworks around the topic [e.g., applying feminist theories of work and family to the issue of water conservation].

Eisenhardt, Kathleen M. “Building Theories from Case Study Research.” Academy of Management Review 14 (October 1989): 532-550; Emmel, Nick. Sampling and Choosing Cases in Qualitative Research: A Realist Approach . Thousand Oaks, CA: SAGE Publications, 2013; Gerring, John. “What Is a Case Study and What Is It Good for?” American Political Science Review 98 (May 2004): 341-354; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Seawright, Jason and John Gerring. "Case Selection Techniques in Case Study Research." Political Research Quarterly 61 (June 2008): 294-308.

Structure and Writing Style

The purpose of a paper in the social sciences designed around a case study is to thoroughly investigate a subject of analysis in order to reveal a new understanding about the research problem and, in so doing, contributing new knowledge to what is already known from previous studies. In applied social sciences disciplines [e.g., education, social work, public administration, etc.], case studies may also be used to reveal best practices, highlight key programs, or investigate interesting aspects of professional work.

In general, the structure of a case study research paper is not all that different from a standard college-level research paper. However, there are subtle differences you should be aware of. Here are the key elements to organizing and writing a case study research paper.

I.  Introduction

As with any research paper, your introduction should serve as a roadmap for your readers to ascertain the scope and purpose of your study . The introduction to a case study research paper, however, should not only describe the research problem and its significance, but you should also succinctly describe why the case is being used and how it relates to addressing the problem. The two elements should be linked. With this in mind, a good introduction answers these four questions:

• What is being studied? Describe the research problem and describe the subject of analysis [the case] you have chosen to address the problem. Explain how they are linked and what elements of the case will help to expand knowledge and understanding about the problem.
• Why is this topic important to investigate? Describe the significance of the research problem and state why a case study design and the subject of analysis that the paper is designed around is appropriate in addressing the problem.
• What did we know about this topic before I did this study? Provide background that helps lead the reader into the more in-depth literature review to follow. If applicable, summarize prior case study research applied to the research problem and why it fails to adequately address the problem. Describe why your case will be useful. If no prior case studies have been used to address the research problem, explain why you have selected this subject of analysis.
• How will this study advance new knowledge or new ways of understanding? Explain why your case study will be suitable in helping to expand knowledge and understanding about the research problem.

Each of these questions should be addressed in no more than a few paragraphs. Exceptions to this can be when you are addressing a complex research problem or subject of analysis that requires more in-depth background information.

II.  Literature Review

The literature review for a case study research paper is generally structured the same as it is for any college-level research paper. The difference, however, is that the literature review is focused on providing background information and  enabling historical interpretation of the subject of analysis in relation to the research problem the case is intended to address . This includes synthesizing studies that help to:

• Place relevant works in the context of their contribution to understanding the case study being investigated . This would involve summarizing studies that have used a similar subject of analysis to investigate the research problem. If there is literature using the same or a very similar case to study, you need to explain why duplicating past research is important [e.g., conditions have changed; prior studies were conducted long ago, etc.].
• Describe the relationship each work has to the others under consideration that informs the reader why this case is applicable . Your literature review should include a description of any works that support using the case to investigate the research problem and the underlying research questions.
• Identify new ways to interpret prior research using the case study . If applicable, review any research that has examined the research problem using a different research design. Explain how your use of a case study design may reveal new knowledge or a new perspective or that can redirect research in an important new direction.
• Resolve conflicts amongst seemingly contradictory previous studies . This refers to synthesizing any literature that points to unresolved issues of concern about the research problem and describing how the subject of analysis that forms the case study can help resolve these existing contradictions.
• Point the way in fulfilling a need for additional research . Your review should examine any literature that lays a foundation for understanding why your case study design and the subject of analysis around which you have designed your study may reveal a new way of approaching the research problem or offer a perspective that points to the need for additional research.
• Expose any gaps that exist in the literature that the case study could help to fill . Summarize any literature that not only shows how your subject of analysis contributes to understanding the research problem, but how your case contributes to a new way of understanding the problem that prior research has failed to do.
• Locate your own research within the context of existing literature [very important!] . Collectively, your literature review should always place your case study within the larger domain of prior research about the problem. The overarching purpose of reviewing pertinent literature in a case study paper is to demonstrate that you have thoroughly identified and synthesized prior studies in relation to explaining the relevance of the case in addressing the research problem.

III.  Method

In this section, you explain why you selected a particular case [i.e., subject of analysis] and the strategy you used to identify and ultimately decide that your case was appropriate in addressing the research problem. The way you describe the methods used varies depending on the type of subject of analysis that constitutes your case study.

If your subject of analysis is an incident or event . In the social and behavioral sciences, the event or incident that represents the case to be studied is usually bounded by time and place, with a clear beginning and end and with an identifiable location or position relative to its surroundings. The subject of analysis can be a rare or critical event or it can focus on a typical or regular event. The purpose of studying a rare event is to illuminate new ways of thinking about the broader research problem or to test a hypothesis. Critical incident case studies must describe the method by which you identified the event and explain the process by which you determined the validity of this case to inform broader perspectives about the research problem or to reveal new findings. However, the event does not have to be a rare or uniquely significant to support new thinking about the research problem or to challenge an existing hypothesis. For example, Walo, Bull, and Breen conducted a case study to identify and evaluate the direct and indirect economic benefits and costs of a local sports event in the City of Lismore, New South Wales, Australia. The purpose of their study was to provide new insights from measuring the impact of a typical local sports event that prior studies could not measure well because they focused on large "mega-events." Whether the event is rare or not, the methods section should include an explanation of the following characteristics of the event: a) when did it take place; b) what were the underlying circumstances leading to the event; and, c) what were the consequences of the event in relation to the research problem.

If your subject of analysis is a person. Explain why you selected this particular individual to be studied and describe what experiences they have had that provide an opportunity to advance new understandings about the research problem. Mention any background about this person which might help the reader understand the significance of their experiences that make them worthy of study. This includes describing the relationships this person has had with other people, institutions, and/or events that support using them as the subject for a case study research paper. It is particularly important to differentiate the person as the subject of analysis from others and to succinctly explain how the person relates to examining the research problem [e.g., why is one politician in a particular local election used to show an increase in voter turnout from any other candidate running in the election]. Note that these issues apply to a specific group of people used as a case study unit of analysis [e.g., a classroom of students].

If your subject of analysis is a place. In general, a case study that investigates a place suggests a subject of analysis that is unique or special in some way and that this uniqueness can be used to build new understanding or knowledge about the research problem. A case study of a place must not only describe its various attributes relevant to the research problem [e.g., physical, social, historical, cultural, economic, political], but you must state the method by which you determined that this place will illuminate new understandings about the research problem. It is also important to articulate why a particular place as the case for study is being used if similar places also exist [i.e., if you are studying patterns of homeless encampments of veterans in open spaces, explain why you are studying Echo Park in Los Angeles rather than Griffith Park?]. If applicable, describe what type of human activity involving this place makes it a good choice to study [e.g., prior research suggests Echo Park has more homeless veterans].

If your subject of analysis is a phenomenon. A phenomenon refers to a fact, occurrence, or circumstance that can be studied or observed but with the cause or explanation to be in question. In this sense, a phenomenon that forms your subject of analysis can encompass anything that can be observed or presumed to exist but is not fully understood. In the social and behavioral sciences, the case usually focuses on human interaction within a complex physical, social, economic, cultural, or political system. For example, the phenomenon could be the observation that many vehicles used by ISIS fighters are small trucks with English language advertisements on them. The research problem could be that ISIS fighters are difficult to combat because they are highly mobile. The research questions could be how and by what means are these vehicles used by ISIS being supplied to the militants and how might supply lines to these vehicles be cut off? How might knowing the suppliers of these trucks reveal larger networks of collaborators and financial support? A case study of a phenomenon most often encompasses an in-depth analysis of a cause and effect that is grounded in an interactive relationship between people and their environment in some way.

NOTE:   The choice of the case or set of cases to study cannot appear random. Evidence that supports the method by which you identified and chose your subject of analysis should clearly support investigation of the research problem and linked to key findings from your literature review. Be sure to cite any studies that helped you determine that the case you chose was appropriate for examining the problem.

IV.  Discussion

The main elements of your discussion section are generally the same as any research paper, but centered around interpreting and drawing conclusions about the key findings from your analysis of the case study. Note that a general social sciences research paper may contain a separate section to report findings. However, in a paper designed around a case study, it is common to combine a description of the results with the discussion about their implications. The objectives of your discussion section should include the following:

Reiterate the Research Problem/State the Major Findings Briefly reiterate the research problem you are investigating and explain why the subject of analysis around which you designed the case study were used. You should then describe the findings revealed from your study of the case using direct, declarative, and succinct proclamation of the study results. Highlight any findings that were unexpected or especially profound.

Explain the Meaning of the Findings and Why They are Important Systematically explain the meaning of your case study findings and why you believe they are important. Begin this part of the section by repeating what you consider to be your most important or surprising finding first, then systematically review each finding. Be sure to thoroughly extrapolate what your analysis of the case can tell the reader about situations or conditions beyond the actual case that was studied while, at the same time, being careful not to misconstrue or conflate a finding that undermines the external validity of your conclusions.

Relate the Findings to Similar Studies No study in the social sciences is so novel or possesses such a restricted focus that it has absolutely no relation to previously published research. The discussion section should relate your case study results to those found in other studies, particularly if questions raised from prior studies served as the motivation for choosing your subject of analysis. This is important because comparing and contrasting the findings of other studies helps support the overall importance of your results and it highlights how and in what ways your case study design and the subject of analysis differs from prior research about the topic.

Consider Alternative Explanations of the Findings Remember that the purpose of social science research is to discover and not to prove. When writing the discussion section, you should carefully consider all possible explanations revealed by the case study results, rather than just those that fit your hypothesis or prior assumptions and biases. Be alert to what the in-depth analysis of the case may reveal about the research problem, including offering a contrarian perspective to what scholars have stated in prior research if that is how the findings can be interpreted from your case.

Acknowledge the Study's Limitations You can state the study's limitations in the conclusion section of your paper but describing the limitations of your subject of analysis in the discussion section provides an opportunity to identify the limitations and explain why they are not significant. This part of the discussion section should also note any unanswered questions or issues your case study could not address. More detailed information about how to document any limitations to your research can be found here .

Suggest Areas for Further Research Although your case study may offer important insights about the research problem, there are likely additional questions related to the problem that remain unanswered or findings that unexpectedly revealed themselves as a result of your in-depth analysis of the case. Be sure that the recommendations for further research are linked to the research problem and that you explain why your recommendations are valid in other contexts and based on the original assumptions of your study.

V.  Conclusion

As with any research paper, you should summarize your conclusion in clear, simple language; emphasize how the findings from your case study differs from or supports prior research and why. Do not simply reiterate the discussion section. Provide a synthesis of key findings presented in the paper to show how these converge to address the research problem. If you haven't already done so in the discussion section, be sure to document the limitations of your case study and any need for further research.

The function of your paper's conclusion is to: 1) reiterate the main argument supported by the findings from your case study; 2) state clearly the context, background, and necessity of pursuing the research problem using a case study design in relation to an issue, controversy, or a gap found from reviewing the literature; and, 3) provide a place to persuasively and succinctly restate the significance of your research problem, given that the reader has now been presented with in-depth information about the topic.

Consider the following points to help ensure your conclusion is appropriate:

• If the argument or purpose of your paper is complex, you may need to summarize these points for your reader.
• If prior to your conclusion, you have not yet explained the significance of your findings or if you are proceeding inductively, use the conclusion of your paper to describe your main points and explain their significance.
• Move from a detailed to a general level of consideration of the case study's findings that returns the topic to the context provided by the introduction or within a new context that emerges from your case study findings.

Note that, depending on the discipline you are writing in or the preferences of your professor, the concluding paragraph may contain your final reflections on the evidence presented as it applies to practice or on the essay's central research problem. However, the nature of being introspective about the subject of analysis you have investigated will depend on whether you are explicitly asked to express your observations in this way.

Problems to Avoid

Overgeneralization One of the goals of a case study is to lay a foundation for understanding broader trends and issues applied to similar circumstances. However, be careful when drawing conclusions from your case study. They must be evidence-based and grounded in the results of the study; otherwise, it is merely speculation. Looking at a prior example, it would be incorrect to state that a factor in improving girls access to education in Azerbaijan and the policy implications this may have for improving access in other Muslim nations is due to girls access to social media if there is no documentary evidence from your case study to indicate this. There may be anecdotal evidence that retention rates were better for girls who were engaged with social media, but this observation would only point to the need for further research and would not be a definitive finding if this was not a part of your original research agenda.

Failure to Document Limitations No case is going to reveal all that needs to be understood about a research problem. Therefore, just as you have to clearly state the limitations of a general research study , you must describe the specific limitations inherent in the subject of analysis. For example, the case of studying how women conceptualize the need for water conservation in a village in Uganda could have limited application in other cultural contexts or in areas where fresh water from rivers or lakes is plentiful and, therefore, conservation is understood more in terms of managing access rather than preserving access to a scarce resource.

Failure to Extrapolate All Possible Implications Just as you don't want to over-generalize from your case study findings, you also have to be thorough in the consideration of all possible outcomes or recommendations derived from your findings. If you do not, your reader may question the validity of your analysis, particularly if you failed to document an obvious outcome from your case study research. For example, in the case of studying the accident at the railroad crossing to evaluate where and what types of warning signals should be located, you failed to take into consideration speed limit signage as well as warning signals. When designing your case study, be sure you have thoroughly addressed all aspects of the problem and do not leave gaps in your analysis that leave the reader questioning the results.

Case Studies. Writing@CSU. Colorado State University; Gerring, John. Case Study Research: Principles and Practices . New York: Cambridge University Press, 2007; Merriam, Sharan B. Qualitative Research and Case Study Applications in Education . Rev. ed. San Francisco, CA: Jossey-Bass, 1998; Miller, Lisa L. “The Use of Case Studies in Law and Social Science Research.” Annual Review of Law and Social Science 14 (2018): TBD; Mills, Albert J., Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Putney, LeAnn Grogan. "Case Study." In Encyclopedia of Research Design , Neil J. Salkind, editor. (Thousand Oaks, CA: SAGE Publications, 2010), pp. 116-120; Simons, Helen. Case Study Research in Practice . London: SAGE Publications, 2009;  Kratochwill,  Thomas R. and Joel R. Levin, editors. Single-Case Research Design and Analysis: New Development for Psychology and Education .  Hilldsale, NJ: Lawrence Erlbaum Associates, 1992; Swanborn, Peter G. Case Study Research: What, Why and How? London : SAGE, 2010; Yin, Robert K. Case Study Research: Design and Methods . 6th edition. Los Angeles, CA, SAGE Publications, 2014; Walo, Maree, Adrian Bull, and Helen Breen. “Achieving Economic Benefits at Local Events: A Case Study of a Local Sports Event.” Festival Management and Event Tourism 4 (1996): 95-106.

Writing Tip

At Least Five Misconceptions about Case Study Research

Social science case studies are often perceived as limited in their ability to create new knowledge because they are not randomly selected and findings cannot be generalized to larger populations. Flyvbjerg examines five misunderstandings about case study research and systematically "corrects" each one. To quote, these are:

Misunderstanding 1 :  General, theoretical [context-independent] knowledge is more valuable than concrete, practical [context-dependent] knowledge. Misunderstanding 2 :  One cannot generalize on the basis of an individual case; therefore, the case study cannot contribute to scientific development. Misunderstanding 3 :  The case study is most useful for generating hypotheses; that is, in the first stage of a total research process, whereas other methods are more suitable for hypotheses testing and theory building. Misunderstanding 4 :  The case study contains a bias toward verification, that is, a tendency to confirm the researcher’s preconceived notions. Misunderstanding 5 :  It is often difficult to summarize and develop general propositions and theories on the basis of specific case studies [p. 221].

While writing your paper, think introspectively about how you addressed these misconceptions because to do so can help you strengthen the validity and reliability of your research by clarifying issues of case selection, the testing and challenging of existing assumptions, the interpretation of key findings, and the summation of case outcomes. Think of a case study research paper as a complete, in-depth narrative about the specific properties and key characteristics of your subject of analysis applied to the research problem.

Flyvbjerg, Bent. “Five Misunderstandings About Case-Study Research.” Qualitative Inquiry 12 (April 2006): 219-245.

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Research Writing and Analysis

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Writing a Case Study

What is a case study?

A Case study is: 

• An in-depth research design that primarily uses a qualitative methodology but sometimes​​ includes quantitative methodology.
• Used to examine an identifiable problem confirmed through research.
• Used to investigate an individual, group of people, organization, or event.
• Used to mostly answer "how" and "why" questions.

What are the different types of case studies?

Note: These are the primary case studies. As you continue to research and learn

about case studies you will begin to find a robust list of different types. 

Who are your case study participants?

What is triangulation ? 

Validity and credibility are an essential part of the case study. Therefore, the researcher should include triangulation to ensure trustworthiness while accurately reflecting what the researcher seeks to investigate.

How to write a Case Study?

When developing a case study, there are different ways you could present the information, but remember to include the five parts for your case study.

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What Is a Case Study and Why You Should Use Them

Case studies can provide more insights into your business while helping you conduct further research with robust qualitative data analysis to learn more.

If you're in charge of running a company, then you're likely always looking for new ways to run your business more efficiently and increase your customer base while streamlining as many processes as possible.

Unfortunately, it can sometimes be difficult to determine how to go about implementing the proper program in order to be successful. This is why many business owners opt to conduct a case study, which can help significantly. Whether you've been struggling with brand consistency or some other problem, the right case study can identify why your problem exists as well as provide a way to rectify it.

A case study is a great tool that many businesses aren't even aware exists, and there are marketing experts like Mailchimp who can provide you with step-by-step assistance with implementing a plan with a case study. Many companies discover that not only do they need to start a blog in order to improve business, but they also need to create specific and relevant blog titles.

If your company already has a blog, then optimizing your blog posts may be helpful. Regardless of the obstacles that are preventing you from achieving all your professional goals, a case study can work wonders in helping you reverse this issue.

What is a case study?

A case study is a comprehensive report of the results of theory testing or examining emerging themes of a business in real life context. Case studies are also often used in the healthcare industry, conducting health services research with primary research interest around routinely collected healthcare data.

However, for businesses, the purpose of a case study is to help small business owners or company leaders identify the issues and conduct further research into what may be preventing success through information collection, client or customer interviews, and in-depth data analysis.

Knowing the case study definition is crucial for any business owner. By identifying the issues that are hindering a company from achieving all its goals, it's easier to make the necessary corrections to promote success through influenced data collection.

Why are case studies important?

Now that we've answered the questions, "what is a case study?" Why are case studies important? Some of the top reasons why case studies are important include:

• Understand complex issues: Even after you conduct a significant amount of market research , you might have a difficult time understanding exactly what it means. While you might have the basics down, conducting a case study can help you see how that information is applied. Then, when you see how the information can make a difference in business decisions, it could make it easier to understand complex issues.
• Collect data: A case study can also help with data tracking . A case study is a data collection method that can help you describe the information that you have available to you. Then, you can present that information in a way the reader can understand.
• Conduct evaluations: As you learn more about how to write a case study, remember that you can also use a case study to conduct evaluations of a specific situation. A case study is a great way to learn more about complex situations, and you can evaluate how various people responded in that situation. By conducting a case study evaluation, you can learn more about what has worked well, what has not, and what you might want to change in the future.
• Identify potential solutions: A case study can also help you identify solutions to potential problems. If you have an issue in your business that you are trying to solve, you may be able to take a look at a case study where someone has dealt with a similar situation in the past. For example, you may uncover data bias in a specific solution that you would like to address when you tackle the issue on your own. If you need help solving a difficult problem, a case study may be able to help you.

Remember that you can also use case studies to target your audience . If you want to show your audience that you have a significant level of expertise in a field, you may want to publish some case studies that you have handled in the past. Then, when your audience sees that you have had success in a specific area, they may be more likely to provide you with their business. In essence, case studies can be looked at as the original method of social proof, showcasing exactly how you can help someone solve their problems.

What are the benefits of writing a business case study?

Although writing a case study can seem like a tedious task, there are many benefits to conducting one through an in depth qualitative research process.

• Industry understanding: First of all, a case study can give you an in-depth understanding of your industry through a particular conceptual framework and help you identify hidden problems that are preventing you from transcending into the business world.
• Develop theories: If you decide to write a business case study, it provides you with an opportunity to develop new theories. You might have a theory about how to solve a specific problem, but you need to write a business case study to see exactly how that theory has unfolded in the past. Then, you can figure out if you want to apply your theory to a similar issue in the future.
• Evaluate interventions: When you write a business case study that focuses on a specific situation you have been through in the past, you can uncover whether that intervention was truly helpful. This can make it easier to figure out whether you want to use the same intervention in a similar situation in the future.
• Identify best practices: If you want to stay on top of the best practices in your field, conducting case studies can help by allowing you to identify patterns and trends and develop a new list of best practices that you can follow in the future.
• Versatility: Writing a case study also provides you with more versatility. If you want to expand your business applications, you need to figure out how you respond to various problems. When you run a business case study, you open the door to new opportunities, new applications, and new techniques that could help you make a difference in your business down the road.
• Solve problems: Writing a great case study can dramatically improve your chances of reversing your problem and improving your business.
• These are just a few of the biggest benefits you might experience if you decide to publish your case studies. They can be an effective tool for learning, showcasing your talents, and teaching some of your other employees. If you want to grow your audience , you may want to consider publishing some case studies.

What are the limitations of case studies?

Case studies can be a wonderful tool for any business of any size to use to gain an in-depth understanding of their clients, products, customers, or services, but there are limitations.

One limitation of case studies is the fact that, unless there are other recently published examples, there is nothing to compare them to since, most of the time, you are conducting a single, not multiple, case studies.

Another limitation is the fact that most case studies can lack scientific evidence.

Types of case studies

There are specific types of case studies to choose from, and each specific type will yield different results. Some case study types even overlap, which is sometimes more favorable, as they provide even more pertinent data.

Here are overviews of the different types of case studies, each with its own theoretical framework, so you can determine which type would be most effective for helping you meet your goals.

Explanatory case studies

Explanatory case studies are pretty straightforward, as they're not difficult to interpret. This type of case study is best if there aren't many variables involved because explanatory case studies can easily answer questions like "how" and "why" through theory development.

Exploratory case studies

An exploratory case study does exactly what its name implies: it goes into specific detail about the topic at hand in a natural, real-life context with qualitative research.

The benefits of exploratory case studies are limitless, with the main one being that it offers a great deal of flexibility. Having flexibility when writing a case study is important because you can't always predict what obstacles might arise during the qualitative research process.

Collective case studies

Collective case studies require you to study many different individuals in order to obtain usable data.

Case studies that involve an investigation of people will involve many different variables, all of which can't be predicted. Despite this fact, there are many benefits of collective case studies, including the fact that it allows an ongoing analysis of the data collected.

Intrinsic case studies

This type of study differs from the others as it focuses on the inquiry of one specific instance among many possibilities.

Many people prefer these types of case studies because it allows them to learn about the particular instance that they wish to investigate further.

Instrumental case studies

An instrumental case study is similar to an intrinsic one, as it focuses on a particular instance, whether it's a person, organization, or something different.

One thing that differentiates instrumental case studies from intrinsic ones is the fact that instrumental case studies aren't chosen merely because a person is interested in learning about a specific instance.

Tips for writing a case study

If you have decided to write case studies for your company, then you may be unsure of where to start or which type to conduct.

However, it doesn't have to be difficult or confusing to begin conducting a case study that will help you identify ways to improve your business.

Here are some helpful tips for writing your case studies:

1. Your case study must be written in the proper format

When writing a case study, the format that you should be similar to this:

Administrative summary

The executive summary is an overview of what your report will contain, written in a concise manner while providing real-life context.

Despite the fact that the executive summary should appear at the beginning of your case studies, it shouldn't be written until you've completed the entire report because if you write it before you finish the report, this summary may not be completely accurate.

Key problem statement

In this section of your case study, you will briefly describe the problem that you hope to solve by conducting the study. You will have the opportunity to elaborate on the problem that you're focusing on as you get into the breadth of the report.

Problem exploration

This part of the case study isn't as brief as the other two, and it goes into more detail about the problem at hand. Your problem exploration must include why the identified problem needs to be solved as well as the urgency of solving it.

Additionally, it must include justification for conducting the problem-solving, as the benefits must outweigh the efforts and costs.

Proposed resolution

This case study section will also be lengthier than the first two. It must include how you propose going about rectifying the problem. The "recommended solution" section must also include potential obstacles that you might experience, as well as how these will be managed.

Furthermore, you will need to list alternative solutions and explain the reason the chosen solution is best. Charts can enhance your report and make it easier to read, and provide as much proof to substantiate your claim as possible.

Overview of monetary consideration

An overview of monetary consideration is essential for all case studies, as it will be used to convince all involved parties why your project should be funded. You must successfully convince them that the cost is worth the investment it will require. It's important that you stress the necessity for this particular case study and explain the expected outcome.

Execution timeline

In the execution times of case studies, you explain how long you predict it will take to implement your study. The shorter the time it will take to implement your plan, the more apt it is to be approved. However, be sure to provide a reasonable timeline, taking into consideration any additional time that might be needed due to obstacles.

Always include a conclusion in your case study. This is where you will briefly wrap up your entire proposal, stressing the benefits of completing the data collection and data analysis in order to rectify your problem.

2. Make it clear and comprehensive

You want to write your case studies with as much clarity as possible so that every aspect of the report is understood. Be sure to double-check your grammar, spelling, punctuation, and more, as you don't want to submit a poorly-written document.

Not only would a poorly-written case study fail to prove that what you are trying to achieve is important, but it would also increase the chances that your report will be tossed aside and not taken seriously.

3. Don't rush through the process

Writing the perfect case study takes time and patience. Rushing could result in your forgetting to include information that is crucial to your entire study. Don't waste your time creating a study that simply isn't ready. Take the necessary time to perform all the research necessary to write the best case study possible.

Depending on the case study, conducting case study research could mean using qualitative methods, quantitative methods, or both. Qualitative research questions focus on non-numerical data, such as how people feel, their beliefs, their experiences, and so on.

Meanwhile, quantitative research questions focus on numerical or statistical data collection to explain causal links or get an in-depth picture.

It is also important to collect insightful and constructive feedback. This will help you better understand the outcome as well as any changes you need to make to future case studies. Consider using formal and informal ways to collect feedback to ensure that you get a range of opinions and perspectives.

4. Be confident in your theory development

While writing your case study or conducting your formal experimental investigation, you should have confidence in yourself and what you're proposing in your report. If you took the time to gather all the pertinent data collected to complete the report, don't second-guess yourself or doubt your abilities. If you believe your report will be amazing, then it likely will be.

5. Case studies and all qualitative research are long

It's expected that multiple case studies are going to be incredibly boring, and there is no way around this. However, it doesn't mean you can choose your language carefully in order to keep your audience as engaged as possible.

If your audience loses interest in your case study at the beginning, for whatever reason, then this increases the likelihood that your case study will not be funded.

Case study examples

If you want to learn more about how to write a case study, it might be beneficial to take a look at a few case study examples. Below are a few interesting case study examples you may want to take a closer look at.

• Phineas Gage by John Martin Marlow : One of the most famous case studies comes from the medical field, and it is about the story of Phineas Gage, a man who had a railroad spike driven through his head in 1848. As he was working on a railroad, an explosive charge went off prematurely, sending a railroad rod through his head. Even though he survived this incident, he lost his left eye. However, Phineas Gage was studied extensively over the years because his experiences had a significant, lasting impact on his personality. This served as a case study because his injury showed different parts of the brain have different functions.
• Kitty Genovese and the bystander effect : This is a tragic case study that discusses the murder of Kitty Genovese, a woman attacked and murdered in Queens, New York City. Shockingly, while numerous neighbors watched the scene, nobody called for help because they assumed someone else would. This case study helped to define the bystander effect, which is when a person fails to intervene during an emergency because other people are around.
• Henry Molaison and the study of memory : Henry Molaison lost his memory and suffered from debilitating amnesia. He suffered from childhood epilepsy, and medical professionals attempted to remove the part of his brain that was causing his seizures. He had a portion of his brain removed, but it completely took away his ability to hold memories. Even though he went on to live until the age of 82, he was always forced to live in the present moment, as he was completely unable to form new memories.

Case study FAQs

When should you do a case study.

There are several scenarios when conducting a case study can be beneficial. Case studies are often used when there's a "why" or "how" question that needs to be answered. Case studies are also beneficial when trying to understand a complex phenomenon, there's limited research on a topic, or when you're looking for practical solutions to a problem.

How can case study results be used to make business decisions?

You can use the results from a case study to make future business decisions if you find yourself in a similar situation. As you assess the results of a case study, you can identify best practices, evaluate the effectiveness of an intervention, generate new and creative ideas, or get a better understanding of customer needs.

How are case studies different from other research methodologies?

When compared to other research methodologies, such as experimental or qualitative research methodology, a case study does not require a representative sample. For example, if you are performing quantitative research, you have a lot of subjects that expand your sample size. If you are performing experimental research, you may have a random sample in front of you. A case study is usually designed to deliberately focus on unusual situations, which allows it to shed new light on a specific business research problem.

Writing multiple case studies for your business

If you're feeling overwhelmed by the idea of writing a case study and it seems completely foreign, then you aren't alone. Writing a case study for a business is a very big deal, but fortunately, there is help available because an example of a case study doesn't always help.

Mailchimp, a well-known marketing company that provides comprehensive marketing support for all sorts of businesses, can assist you with your case study, or you can review one of their own recently published examples.

Mailchimp can assist you with developing the most effective content strategy to increase your chances of being as successful as possible. Mailchimp's content studio is a great tool that can help your business immensely.

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Blog Beginner Guides What is a Case Study? [+6 Types of Case Studies]

What is a Case Study? [+6 Types of Case Studies]

Written by: Ronita Mohan Sep 20, 2021

Case studies have become powerful business tools. But what is a case study? What are the benefits of creating one? Are there limitations to the format?

If you’ve asked yourself these questions, our helpful guide will clear things up. Learn how to use a case study for business. Find out how cases analysis works in psychology and research.

We’ve also got examples of case studies to inspire you.

Haven’t made a case study before? You can easily  create a case study  with Venngage’s customizable templates.

CREATE A CASE STUDY

Click to jump ahead:

What is a case study, what is the case study method, benefits of case studies, limitations of case studies, types of case studies, faqs about case studies.

Case studies are research methodologies. They examine subjects, projects, or organizations to tell a story.

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Numerous sectors use case analyses. The social sciences, social work, and psychology create studies regularly.

Healthcare industries write reports on patients and diagnoses. Marketing case study examples , like the one below, highlight the benefits of a business product.

CREATE THIS REPORT TEMPLATE

Now that you know what a case study is, we explain how case reports are used in three different industries.

What is a business case study?

A business or marketing case study aims at showcasing a successful partnership. This can be between a brand and a client. Or the case study can examine a brand’s project.

There is a perception that case studies are used to advertise a brand. But effective reports, like the one below, can show clients how a brand can support them.

Hubspot created a case study on a customer that successfully scaled its business. The report outlines the various Hubspot tools used to achieve these results.

Hubspot also added a video with testimonials from the client company’s employees.

So, what is the purpose of a case study for businesses? There is a lot of competition in the corporate world. Companies are run by people. They can be on the fence about which brand to work with.

Business reports  stand out aesthetically, as well. They use  brand colors  and brand fonts . Usually, a combination of the client’s and the brand’s.

With the Venngage  My Brand Kit  feature, businesses can automatically apply their brand to designs.

A business case study, like the one below, acts as social proof. This helps customers decide between your brand and your competitors.

Don’t know how to design a report? You can learn  how to write a case study  with Venngage’s guide. We also share design tips and examples that will help you convert.

Related: 55+ Annual Report Design Templates, Inspirational Examples & Tips [Updated]

What is a case study in psychology?

In the field of psychology, case studies focus on a particular subject. Psychology case histories also examine human behaviors.

Case reports search for commonalities between humans. They are also used to prescribe further research. Or these studies can elaborate on a solution for a behavioral ailment.

The American Psychology Association  has a number of case studies on real-life clients. Note how the reports are more text-heavy than a business case study.

Famous psychologists such as Sigmund Freud and Anna O popularised the use of case studies in the field. They did so by regularly interviewing subjects. Their detailed observations build the field of psychology.

It is important to note that psychological studies must be conducted by professionals. Psychologists, psychiatrists and therapists should be the researchers in these cases.

Related: What Netflix’s Top 50 Shows Can Teach Us About Font Psychology [Infographic]

What is a case study in research?

Research is a necessary part of every case study. But specific research fields are required to create studies. These fields include user research, healthcare, education, or social work.

For example, this UX Design  report examined the public perception of a client. The brand researched and implemented new visuals to improve it. The study breaks down this research through lessons learned.

Clinical reports are a necessity in the medical field. These documents are used to share knowledge with other professionals. They also help examine new or unusual diseases or symptoms.

The pandemic has led to a significant increase in research. For example,  Spectrum Health  studied the value of health systems in the pandemic. They created the study by examining community outreach.

The pandemic has significantly impacted the field of education. This has led to numerous examinations on remote studying. There have also been studies on how students react to decreased peer communication.

Social work case reports often have a community focus. They can also examine public health responses. In certain regions, social workers study disaster responses.

You now know what case studies in various fields are. In the next step of our guide, we explain the case study method.

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A case analysis is a deep dive into a subject. To facilitate this case studies are built on interviews and observations. The below example would have been created after numerous interviews.

Case studies are largely qualitative. They analyze and describe phenomena. While some data is included, a case analysis is not quantitative.

There are a few steps in the case method. You have to start by identifying the subject of your study. Then determine what kind of research is required.

In natural sciences, case studies can take years to complete. Business reports, like this one, don’t take that long. A few weeks of interviews should be enough.

The case method will vary depending on the industry. Reports will also look different once produced.

As you will have seen, business reports are more colorful. The design is also more accessible . Healthcare and psychology reports are more text-heavy.

Designing case reports takes time and energy. So, is it worth taking the time to write them? Here are the benefits of creating case studies.

• Collects large amounts of information
• Helps formulate hypotheses
• Builds the case for further research
• Discovers new insights into a subject
• Builds brand trust and loyalty
• Engages customers through stories

For example, the business study below creates a story around a brand partnership. It makes for engaging reading. The study also shows evidence backing up the information.

We’ve shared the benefits of why studies are needed. We will also look at the limitations of creating them.

Related: How to Present a Case Study like a Pro (With Examples)

There are a few disadvantages to conducting a case analysis. The limitations will vary according to the industry.

• Responses from interviews are subjective
• Subjects may tailor responses to the researcher
• Studies can’t always be replicated
• In certain industries, analyses can take time and be expensive
• Risk of generalizing the results among a larger population

These are some of the common weaknesses of creating case reports. If you’re on the fence, look at the competition in your industry.

Other brands or professionals are building reports, like this example. In that case, you may want to do the same.

There are six common types of case reports. Depending on your industry, you might use one of these types.

Descriptive case studies

Explanatory case studies, exploratory case reports, intrinsic case studies, instrumental case studies, collective case reports.

USE THIS TEMPLATE

We go into more detail about each type of study in the guide below.

Related:  15+ Professional Case Study Examples [Design Tips + Templates]

When you have an existing hypothesis, you can design a descriptive study. This type of report starts with a description. The aim is to find connections between the subject being studied and a theory.

Once these connections are found, the study can conclude. The results of this type of study will usually suggest how to develop a theory further.

A study like the one below has concrete results. A descriptive report would use the quantitative data as a suggestion for researching the subject deeply.

When an incident occurs in a field, an explanation is required. An explanatory report investigates the cause of the event. It will include explanations for that cause.

The study will also share details about the impact of the event. In most cases, this report will use evidence to predict future occurrences. The results of explanatory reports are definitive.

Note that there is no room for interpretation here. The results are absolute.

The study below is a good example. It explains how one brand used the services of another. It concludes by showing definitive proof that the collaboration was successful.

Another example of this study would be in the automotive industry. If a vehicle fails a test, an explanatory study will examine why. The results could show that the failure was because of a particular part.

Related: How to Write a Case Study [+ Design Tips]

An explanatory report is a self-contained document. An exploratory one is only the beginning of an investigation.

Exploratory cases act as the starting point of studies. This is usually conducted as a precursor to large-scale investigations. The research is used to suggest why further investigations are needed.

An exploratory study can also be used to suggest methods for further examination.

For example, the below analysis could have found inconclusive results. In that situation, it would be the basis for an in-depth study.

Intrinsic studies are more common in the field of psychology. These reports can also be conducted in healthcare or social work.

These types of studies focus on a unique subject, such as a patient. They can sometimes study groups close to the researcher.

The aim of such studies is to understand the subject better. This requires learning their history. The researcher will also examine how they interact with their environment.

For instance, if the case study below was about a unique brand, it could be an intrinsic study.

Once the study is complete, the researcher will have developed a better understanding of a phenomenon. This phenomenon will likely not have been studied or theorized about before.

Examples of intrinsic case analysis can be found across psychology. For example, Jean Piaget’s theories on cognitive development. He established the theory from intrinsic studies into his own children.

Related: What Disney Villains Can Tell Us About Color Psychology [Infographic]

This is another type of study seen in medical and psychology fields. Instrumental reports are created to examine more than just the primary subject.

When research is conducted for an instrumental study, it is to provide the basis for a larger phenomenon. The subject matter is usually the best example of the phenomenon. This is why it is being studied.

Assume it’s examining lead generation strategies. It may want to show that visual marketing is the definitive lead generation tool. The brand can conduct an instrumental case study to examine this phenomenon.

Collective studies are based on instrumental case reports. These types of studies examine multiple reports.

There are a number of reasons why collective reports are created:

• To provide evidence for starting a new study
• To find pattens between multiple instrumental reports
• To find differences in similar types of cases
• Gain a deeper understanding of a complex phenomenon
• Understand a phenomenon from diverse contexts

A researcher could use multiple reports, like the one below, to build a collective case report.

Related: 10+ Case Study Infographic Templates That Convert

What makes a case study a case study?

A case study has a very particular research methodology. They are an in-depth study of a person or a group of individuals. They can also study a community or an organization. Case reports examine real-world phenomena within a set context.

How long should a case study be?

The length of studies depends on the industry. It also depends on the story you’re telling. Most case studies should be at least 500-1500 words long. But you can increase the length if you have more details to share.

What should you ask in a case study?

The one thing you shouldn’t ask is ‘yes’ or ‘no’ questions. Case studies are qualitative. These questions won’t give you the information you need.

Ask your client about the problems they faced. Ask them about solutions they found. Or what they think is the ideal solution. Leave room to ask them follow-up questions. This will help build out the study.

How to present a case study?

When you’re ready to present a case study, begin by providing a summary of the problem or challenge you were addressing. Follow this with an outline of the solution you implemented, and support this with the results you achieved, backed by relevant data. Incorporate visual aids like slides, graphs, and images to make your case study presentation more engaging and impactful.

Now you know what a case study means, you can begin creating one. These reports are a great tool for analyzing brands. They are also useful in a variety of other fields.

Use a visual communication platform like Venngage to design case studies. With Venngage’s templates, you can design easily. Create branded, engaging reports, all without design experience.

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What the Case Study Method Really Teaches

• Nitin Nohria

Seven meta-skills that stick even if the cases fade from memory.

It’s been 100 years since Harvard Business School began using the case study method. Beyond teaching specific subject matter, the case study method excels in instilling meta-skills in students. This article explains the importance of seven such skills: preparation, discernment, bias recognition, judgement, collaboration, curiosity, and self-confidence.

During my decade as dean of Harvard Business School, I spent hundreds of hours talking with our alumni. To enliven these conversations, I relied on a favorite question: “What was the most important thing you learned from your time in our MBA program?”

• Nitin Nohria is the George F. Baker Jr. and Distinguished Service University Professor. He served as the 10th dean of Harvard Business School, from 2010 to 2020.

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Case Study Research Method in Psychology

Saul Mcleod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul Mcleod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Learn about our Editorial Process

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

On This Page:

Case studies are in-depth investigations of a person, group, event, or community. Typically, data is gathered from various sources using several methods (e.g., observations & interviews).

The case study research method originated in clinical medicine (the case history, i.e., the patient’s personal history). In psychology, case studies are often confined to the study of a particular individual.

The information is mainly biographical and relates to events in the individual’s past (i.e., retrospective), as well as to significant events that are currently occurring in his or her everyday life.

The case study is not a research method, but researchers select methods of data collection and analysis that will generate material suitable for case studies.

Freud (1909a, 1909b) conducted very detailed investigations into the private lives of his patients in an attempt to both understand and help them overcome their illnesses.

This makes it clear that the case study is a method that should only be used by a psychologist, therapist, or psychiatrist, i.e., someone with a professional qualification.

There is an ethical issue of competence. Only someone qualified to diagnose and treat a person can conduct a formal case study relating to atypical (i.e., abnormal) behavior or atypical development.

 Famous Case Studies

• Anna O – One of the most famous case studies, documenting psychoanalyst Josef Breuer’s treatment of “Anna O” (real name Bertha Pappenheim) for hysteria in the late 1800s using early psychoanalytic theory.
• Little Hans – A child psychoanalysis case study published by Sigmund Freud in 1909 analyzing his five-year-old patient Herbert Graf’s house phobia as related to the Oedipus complex.
• Bruce/Brenda – Gender identity case of the boy (Bruce) whose botched circumcision led psychologist John Money to advise gender reassignment and raise him as a girl (Brenda) in the 1960s.
• Genie Wiley – Linguistics/psychological development case of the victim of extreme isolation abuse who was studied in 1970s California for effects of early language deprivation on acquiring speech later in life.
• Phineas Gage – One of the most famous neuropsychology case studies analyzes personality changes in railroad worker Phineas Gage after an 1848 brain injury involving a tamping iron piercing his skull.

Clinical Case Studies

• Studying the effectiveness of psychotherapy approaches with an individual patient
• Assessing and treating mental illnesses like depression, anxiety disorders, PTSD
• Neuropsychological cases investigating brain injuries or disorders

Child Psychology Case Studies

• Studying psychological development from birth through adolescence
• Cases of learning disabilities, autism spectrum disorders, ADHD
• Effects of trauma, abuse, deprivation on development

Types of Case Studies

• Explanatory case studies : Used to explore causation in order to find underlying principles. Helpful for doing qualitative analysis to explain presumed causal links.
• Exploratory case studies : Used to explore situations where an intervention being evaluated has no clear set of outcomes. It helps define questions and hypotheses for future research.
• Descriptive case studies : Describe an intervention or phenomenon and the real-life context in which it occurred. It is helpful for illustrating certain topics within an evaluation.
• Multiple-case studies : Used to explore differences between cases and replicate findings across cases. Helpful for comparing and contrasting specific cases.
• Intrinsic : Used to gain a better understanding of a particular case. Helpful for capturing the complexity of a single case.
• Collective : Used to explore a general phenomenon using multiple case studies. Helpful for jointly studying a group of cases in order to inquire into the phenomenon.

Where Do You Find Data for a Case Study?

There are several places to find data for a case study. The key is to gather data from multiple sources to get a complete picture of the case and corroborate facts or findings through triangulation of evidence. Most of this information is likely qualitative (i.e., verbal description rather than measurement), but the psychologist might also collect numerical data.

1. Primary sources

• Interviews – Interviewing key people related to the case to get their perspectives and insights. The interview is an extremely effective procedure for obtaining information about an individual, and it may be used to collect comments from the person’s friends, parents, employer, workmates, and others who have a good knowledge of the person, as well as to obtain facts from the person him or herself.
• Observations – Observing behaviors, interactions, processes, etc., related to the case as they unfold in real-time.
• Documents & Records – Reviewing private documents, diaries, public records, correspondence, meeting minutes, etc., relevant to the case.

2. Secondary sources

• News/Media – News coverage of events related to the case study.
• Academic articles – Journal articles, dissertations etc. that discuss the case.
• Government reports – Official data and records related to the case context.
• Books/films – Books, documentaries or films discussing the case.

3. Archival records

Searching historical archives, museum collections and databases to find relevant documents, visual/audio records related to the case history and context.

Public archives like newspapers, organizational records, photographic collections could all include potentially relevant pieces of information to shed light on attitudes, cultural perspectives, common practices and historical contexts related to psychology.

4. Organizational records

Organizational records offer the advantage of often having large datasets collected over time that can reveal or confirm psychological insights.

Of course, privacy and ethical concerns regarding confidential data must be navigated carefully.

However, with proper protocols, organizational records can provide invaluable context and empirical depth to qualitative case studies exploring the intersection of psychology and organizations.

• Organizational/industrial psychology research : Organizational records like employee surveys, turnover/retention data, policies, incident reports etc. may provide insight into topics like job satisfaction, workplace culture and dynamics, leadership issues, employee behaviors etc.
• Clinical psychology : Therapists/hospitals may grant access to anonymized medical records to study aspects like assessments, diagnoses, treatment plans etc. This could shed light on clinical practices.
• School psychology : Studies could utilize anonymized student records like test scores, grades, disciplinary issues, and counseling referrals to study child development, learning barriers, effectiveness of support programs, and more.

How do I Write a Case Study in Psychology?

Follow specified case study guidelines provided by a journal or your psychology tutor. General components of clinical case studies include: background, symptoms, assessments, diagnosis, treatment, and outcomes. Interpreting the information means the researcher decides what to include or leave out. A good case study should always clarify which information is the factual description and which is an inference or the researcher’s opinion.

1. Introduction

• Provide background on the case context and why it is of interest, presenting background information like demographics, relevant history, and presenting problem.
• Compare briefly to similar published cases if applicable. Clearly state the focus/importance of the case.

2. Case Presentation

• Describe the presenting problem in detail, including symptoms, duration,and impact on daily life.
• Include client demographics like age and gender, information about social relationships, and mental health history.
• Describe all physical, emotional, and/or sensory symptoms reported by the client.
• Use patient quotes to describe the initial complaint verbatim. Follow with full-sentence summaries of relevant history details gathered, including key components that led to a working diagnosis.
• Summarize clinical exam results, namely orthopedic/neurological tests, imaging, lab tests, etc. Note actual results rather than subjective conclusions. Provide images if clearly reproducible/anonymized.
• Clearly state the working diagnosis or clinical impression before transitioning to management.

3. Management and Outcome

• Indicate the total duration of care and number of treatments given over what timeframe. Use specific names/descriptions for any therapies/interventions applied.
• Present the results of the intervention,including any quantitative or qualitative data collected.
• For outcomes, utilize visual analog scales for pain, medication usage logs, etc., if possible. Include patient self-reports of improvement/worsening of symptoms. Note the reason for discharge/end of care.

4. Discussion

• Analyze the case, exploring contributing factors, limitations of the study, and connections to existing research.
• Analyze the effectiveness of the intervention,considering factors like participant adherence, limitations of the study, and potential alternative explanations for the results.
• Identify any questions raised in the case analysis and relate insights to established theories and current research if applicable. Avoid definitive claims about physiological explanations.
• Offer clinical implications, and suggest future research directions.

5. Additional Items

• Thank specific assistants for writing support only. No patient acknowledgments.
• References should directly support any key claims or quotes included.
• Use tables/figures/images only if substantially informative. Include permissions and legends/explanatory notes.
• Provides detailed (rich qualitative) information.
• Provides insight for further research.
• Permitting investigation of otherwise impractical (or unethical) situations.

Case studies allow a researcher to investigate a topic in far more detail than might be possible if they were trying to deal with a large number of research participants (nomothetic approach) with the aim of ‘averaging’.

Because of their in-depth, multi-sided approach, case studies often shed light on aspects of human thinking and behavior that would be unethical or impractical to study in other ways.

Research that only looks into the measurable aspects of human behavior is not likely to give us insights into the subjective dimension of experience, which is important to psychoanalytic and humanistic psychologists.

Case studies are often used in exploratory research. They can help us generate new ideas (that might be tested by other methods). They are an important way of illustrating theories and can help show how different aspects of a person’s life are related to each other.

The method is, therefore, important for psychologists who adopt a holistic point of view (i.e., humanistic psychologists ).

Limitations

• Lacking scientific rigor and providing little basis for generalization of results to the wider population.
• Researchers’ own subjective feelings may influence the case study (researcher bias).
• Difficult to replicate.
• Time-consuming and expensive.
• The volume of data, together with the time restrictions in place, impacted the depth of analysis that was possible within the available resources.

Because a case study deals with only one person/event/group, we can never be sure if the case study investigated is representative of the wider body of “similar” instances. This means the conclusions drawn from a particular case may not be transferable to other settings.

Because case studies are based on the analysis of qualitative (i.e., descriptive) data , a lot depends on the psychologist’s interpretation of the information she has acquired.

This means that there is a lot of scope for Anna O , and it could be that the subjective opinions of the psychologist intrude in the assessment of what the data means.

For example, Freud has been criticized for producing case studies in which the information was sometimes distorted to fit particular behavioral theories (e.g., Little Hans ).

This is also true of Money’s interpretation of the Bruce/Brenda case study (Diamond, 1997) when he ignored evidence that went against his theory.

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Further Information

• Case Study Approach
• Case Study Method
• Enhancing the Quality of Case Studies in Health Services Research
• “We do things together” A case study of “couplehood” in dementia
• Using mixed methods for evaluating an integrative approach to cancer care: a case study

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Visualizing hidden communities of interest: A case-study analysis of topic-based social networks in astrobiology

• Published: 27 May 2024

Cite this article

• Christophe Malaterre   ORCID: orcid.org/0000-0003-1413-6710 1 , 2 &
• Francis Lareau   ORCID: orcid.org/0000-0002-0352-5246 3  

Author networks in science often rely on citation analyses. In such cases, as in others, network interpretation usually depends on supplementary data, notably about authors’ research domains when disciplinary interpretations are sought. More general social networks also face similar interpretation challenges as to the semantic content specificities of their members. In this research-in-progress, we propose to infer author networks not from citation analyses but from topic similarity analyses based on a topic-model of published documents. Such author networks reveal, as we call them, “hidden communities of interest” (HCoIs) whose semantic content can easily be interpreted by means of their associated topics in the model. We use an astrobiology corpus of full-text articles ( N  = 3,698) to illustrate the approach. Having conducted an LDA topic-model on all publications, we identify the underlying communities of authors by measuring author correlations in terms of topic distributions. Adding publication dates makes it possible to examine HCoI evolution over time. This approach to social networks supplements traditional methods in contexts where textual data are available.

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Abbreviations

• Hidden communities of interest

Social network analysis

Latent Dirichlet analysis

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Acknowledgements

C.M. acknowledges funding from Canada Social Sciences and Humanities Research Council (Grant 430-2018-00899) and Canada Research Chairs (CRC-950-230795). F.L. acknowledges funding from the Canada Social Sciences and Humanities Research Council (756-2024-0557) and the Canada Research Chair in Philosophy of the Life Sciences at UQAM. The authors thank the audience of ISSI 2023 for most helpful comments on an earlier version of this paper published in the conference proceedings as: Malaterre, C., & Lareau, F. (2023). Visualizing hidden communities of interest: A preliminary analysis of topic-based social networks in astrobiology. Proceedings of ISSI 2023 . The 19th Conference of the International Society for Scientometrics and Informetrics, Bloomington, IN.

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Malaterre, C., Lareau, F. Visualizing hidden communities of interest: A case-study analysis of topic-based social networks in astrobiology. Scientometrics (2024). https://doi.org/10.1007/s11192-024-05047-7

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Hemodynamic parameters and diabetes mellitus in community-dwelling middle-aged adults and elders: a community-based study

• Tzu-Wei Wu 1 ,
• Yih-Jer Wu 1 , 2 , 3 , 4 ,
• Chao-Liang Chou 1 , 5 ,
• Chun-Fang Cheng 6 ,
• Shu-Xin Lu 5 &
• Li-Yu Wang 1  

Scientific Reports volume  14 , Article number:  12032 ( 2024 ) Cite this article

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• Prognostic markers

Hemodynamic parameters have been correlated with stroke, hypertension, and arterial stenosis. While only a few small studies have examined the link between hemodynamics and diabetes mellitus (DM). This case-control study enrolled 417 DM patients and 3475 non-DM controls from a community-based cohort. Peak systolic velocity (PSV), end-diastolic velocity (EDV), blood flow velocity (MFV), pulsatility index (PI), and the resistance index (RI) of the common carotid arteries were measured by color Doppler ultrasonography. Generalized linear regression analyses showed that as compared to the non-DM controls, the age-sex-adjusted means of PSV, EDV, and MFV were − 3.28 cm/sec, − 1.94 cm/sec, and − 2.38 cm/sec, respectively, lower and the age-sex-adjusted means of RI and PI were 0.013 and 0.0061, respectively, higher for the DM cases (all p -values < 0.0005). As compared to the lowest quartiles, the multivariable-adjusted ORs of DM for the highest quartiles of PSV, EDV, MFV, RI, and PI were 0.59 (95% confidence interval [CI] 0.41–0.83), 0.45 (95% CI 0.31–0.66), 0.53 (95% CI 0.37–0.77), 1.61 (95% CI 1.15–2.25), and 1.58 (95% CI 1.12–2.23), respectively. More importantly, the additions of EDV significantly improved the predictabilities of the regression models on DM. As compared to the model contained conventional CVD risk factors alone, the area under the receiver operating curve (AUROC) increased by 1.00% (95% CI 0.29–1.73%; p  = 0.0059) and 0.80% (95% CI 0.15–1.46%; p  = 0.017) for models that added EDV in continuous and quartile scales, respectively. Additionally, the additions of PSV and MFV also significantly improved the predictabilities of the regression models (all 0.01 <  p -value < 0.05). This study reveals a significant correlation between DM and altered hemodynamic parameters. Understanding this relationship could help identify individuals at higher risk of DM and facilitate targeted preventive strategies to reduce cardiovascular complications in DM patients.

Atherosclerosis is a chronic disease that causes the occlusion of arteries by the accumulation of plaques within the arterial intima 1 . These plaques consist of lipids, predominantly low-density lipoprotein (LDL), and inflammatory cells, such as macrophages that transform into foam cells after phagocytosing lipids 2 , 3 . Atherosclerosis advances gradually and often asymptomatically, but it can be aggravated by other factors such as hypertension 4 . As the plaques enlarge, they can impair blood flow and induce shear stress in the vessel wall. This can provoke the erosion of vulnerable plaques and the generation of thrombi that can occlude the artery or embolize other organs 5 . Atherosclerosis can result in severe cardiovascular complications such as myocardial infarction and stroke, which are among the leading causes of mortality worldwide 6 , 7 . Atherosclerosis is especially common in developed countries, but it is also increasing in developing countries 8 . In Taiwan, for instance, five of the top ten causes of mortality are associated with atherosclerosis 9 .

Hemodynamics is the study of blood flow and the forces acting on the blood vessels and the heart. The relationship between atherosclerosis and hemodynamics is complex and bidirectional. On one hand, hemodynamic shear stress can influence the development and progression of atherosclerosis by modulating the phenotype and function of endothelial cells and smooth muscle cells, and by promoting or inhibiting inflammation, oxidative stress, lipid accumulation, and matrix remodeling in the arterial wall 10 , 11 , 12 . On the other hand, atherosclerosis can alter the geometry and elasticity of the arteries, which can affect the hemodynamic patterns and parameters such as pressure, flow, velocity, and shear stress 13 . These changes can further influence the stability and rupture risk of atherosclerotic plaques. Key hemodynamic parameters include peak systolic velocity (PSV), end-diastolic velocity (EDV), and mean blood flow velocity (MFV) measured by Doppler ultrasonography. Pulsatility index (PI) and resistance index (RI) were secondary parameters calculated from velocities 14 , 15 and were accepted as methods of examing microcirculation with a variety of clinical applications 16 . PI is defined as the difference between PSV and EDV, divided by MFV, and RI is defined as the difference between PSV and EDV, divided by PSV.

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia that induces polyuria, polydipsia, and polyphagia. DM results from inadequate insulin secretion and/or impaired insulin action in the target tissues 17 . There are two main types of diabetes: type 1 and type 2. Type 1 diabetes is an autoimmune disease that causes β-cell destruction in the pancreatic islets. It typically manifests in children and adolescents and necessitates exogenous insulin therapy. Type 2 diabetes is more prevalent and involves insulin resistance that exacerbates as the β-cell function deteriorates 18 . DM affects over 450 million people worldwide and accounts for 4.2 million deaths annually 19 . DM is diagnosed by assessing fasting and post-load plasma glucose levels.

Clinically, DM is associated with increased risks of vascular events, including carotid artery diseases 20 , 21 . Our previous study demonstrated the prevalence of DM is significantly associated with the development and severity of carotid atherosclerosis 22 . Later we identified 9 DM SNPs showing promising associations with the presence of carotid plaque in a community-based case-control study 23 . The associations of hemodynamics and carotid pulsatility with DM were noted in a few studies previously 24 , 25 , 26 . However, this clinical correlation is not fully explored. In this community-based case-control study, the relationship between DM and hemodynamic parameters was investigated in more than 3800 subjects, including 417 DM patients and 3475 non-DM controls, from the Northern coast of Taiwan.

Study subjects

The study subjects were recruited from our two previous community-based cohort studies that enrolled 40–74-year-old middle-aged adults and elders residing in the five districts in the northern coastal area of Taiwan for at least six months 22 , 27 . Cohort I and II enrolled study subjects from September 2010 to May 2011 and from September 2014 to May 2020, respectively. During each period, well-informed invitation letters describing the objective and protocols of the study were sent to households with eligible subject(s), and recruitment sites were set up at the local health stations, schools, or community activity centers. Residents who were willing to complete a structured questionnaire regarding personal health information and willing to provide blood samples were recruited. A total of 4102 residents voluntarily provided informed consent and were enrolled. Subjects who had a positive history of physician-diagnosed myocardial infarction or had ever received a cardiac catheter or stent (n = 165) and who were without a proper flow pattern sample (n = 45) were excluded, leaving a total of 3892 middle-aged adults and elders in this study. The study complied with the 1975 Helsinki Declaration on ethics in medical research and was reviewed and approved by the institutional review boards of MacKay Medical College (No. P990001) and MacKay Memorial Hospital (No. 14MMHIS075).

Anthropometric and biochemical measurements

The measurements of baseline anthropometric and clinical characteristics were described previously 27 , 28 . In brief, blood pressure was measured three times by a digital system (UDEX-Twin; ELK Co., Daejon, Korea) in the morning after 10 min of rest. Three blood pressure measurements, with an interval of ≥ 3 minutes, were made for each participant. The averages of repeated measurements of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were used for analyses.

A venous blood sample was collected from each participant for blood lipids and glucose analyses after at least 10 hours of fasting. We used an autoanalyzer (Toshiba TBA c16000; Toshiba Medical System, Holliston, MA, USA) to determine the blood levels of lipids, including total cholesterol (TCHO), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (FTG), and glucose (FPG) with commercial kits (Denka Seiken, Tokyo, Japan).

In this study, DM was defined as FPG ≥ 126 mg/dL or the use of insulin or other hypoglycemic agents. Hypertension was defined as SBP ≥ 140 mmHg, DBP ≥ 90 mmHg, or a history of taking antihypertensive medications. Current cigarette smoking was defined as having smoked cigarettes at least 4 days per week during the past month before enrollment. Current alcohol drinking was defined as having drunk alcohol-containing beverages at least 4 days per week during the past month before enrollment.

Ultrasonographic measurements of carotid blood flow

In the study, blood flows, including PSV, EDV, and MFV, of extracranial carotid arteries, were measured at the middle segment of the bilateral common carotid arteries by color Doppler ultrasonography. The ultrasonographic systems (GE Healthcare Logie E, Vivid 7, and Vivid E9; General Electric Company, Milwaukee, USA), which were equipped with a multi-frequency linear array transducer, were operated by two experienced technicians who were blind to patients’ clinical profiles. Each participant was examined in the supine position with his/her head turned 45° from the site being measured. An insonation angle equal to or less than 60° and a sample volume size covering 1/2–2/3 of the arterial lumen were maintained for all Doppler measurements. In the study, a proper flow pattern sample was defined as subjects with at least 3 waveforms with similar patterns. The subject’s PI and RI were calculated as (PSV-EDV)/MFV and (PSV-EDV)/PSV, respectively. In the study, the averages of the measurements of the right and left common carotid arteries were used for statistical analyses.

Statistical analyses

In this study, the student t-test and one-way analysis of variance were used to test the significance of means of continuous measurements among groups. Logarithmic transformation was performed for continuous random variables with positive skewness. The Chi-square test was used to test the significance of the associations between DM status and categorical variables. The effects of age, sex, and DM on the carotid hemodynamic parameters were assessed by the generalized linear regression analyses. The odds ratio (OR), which was estimated by the unconditional logistic regression model, was used as the indicator of the strength of association between carotid hemodynamic parameters and DM status. To assess the independent effects of carotid hemodynamic parameters on DM, we used multivariable logistic regression analyses to control for the confounding effects of other conventional cardiovascular risk factors. The area under the receiver operating curve (AUROC) was used as the indicator of the predictability of the regression model on DM. To explore whether there were interactions between hemodynamic biomarkers and other significant factors on the likelihoods of having DM, we carried out stratified analyses. For continuous variables, the values close to the medians in the non-DM subjects were used as the cut-points. We used the statistical method proposed by Clogg et al. 29 to test the significance in the regression coefficients between two groups. All statistical analyses were performed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA).

Ethics approval and consent to participate

The study complied with the 1975 Helsinki Declaration on ethics in medical research and was reviewed and approved by the institutional review boards of MacKay Medical College (No. P990001, granted date: 2010/7/5) and MacKay Memorial Hospital (No. 14MMHIS075, Granted date: 2014/5/23).

Among 3892 participants, 417 (10.7%) of them fulfilled the DM definition and were regarded as cases. Table 1 shows that all baseline anthropometric and biochemical measurements, except for alcohol drinking, were significantly different between DM cases and non-DM controls. As compared to the non-DM controls, DM cases had significantly higher means of age, body mass index (BMI), waist circumference (WC), hip circumference (HIP), waist-to-hip ratio (WHR), blood pressure, and Log (TG) and higher proportions of the male sex, hypertension, schooling years < 12 years, and cigarette smoking. The means of TCHO, LDL-C, and HDL-C of DM cases were significantly lower than those of the non-DM controls.

Multivariable logistic regression analyses of the conventional cardiovascular risk factors showed that older age, hypertension, fewer schooling years, cigarette smoking, higher BMI, higher WHR, and higher TG were correlated with significantly higher ORs of having DM (Table 2 ). The multivariable-adjusted ORs of having DM with TCHO and HDL-C levels were significantly inverse. The multivariable-adjusted ORs for per 1.0 SD increases in BMI, WHR, TCHO, HDL-C, and log(TG) were 1.24 (95% CI 1.11–1.40), 1.30 (95% CI 1.14–1.48), 0.77 (95% CI 0.67–0.87), 0.84 (95% CI 0.71–0.99), and 1.98 (95% CI 1.56–2.51) respectively.

The effects of age, sex, and DM on carotid blood flows, RI, and PI are shown in Table 3 . As compared to female subjects, male subjects had significantly higher means of PSV, PI, and RI and significantly lower means of EDV and MFV (all p -values < 0.0001). The means of these five carotid hemodynamic parameters were all significantly different among seven age groups (all p -values < 0.0001). The means (SD) of PSV, EDV, and MFV for subjects aged 40–44 years were 95.1 (17.6) cm/sec, 26.1 (5.6) cm/sec, and 44.4 (8.0) cm/sec, respectively, for subjects aged 55–59 years were 84.5 (17.4) cm/sec, 24.4 (5.4) cm/sec, and 41.4 (7.9) cm/sec, respectively, and for subjects aged 70–74 years were 75.9 (16.7) cm/sec, 18.2 (4.6) cm/sec, and 34.5 (7.2) cm/sec, respectively. The means of RI and PI were lower for subjects aged 45–54 years and were higher for elderly subjects. Table 3 also shows that DM cases had significantly lower means of PSV, EDV, and MFV and significantly higher means of RI and PI as compared to the non-DM controls (all p -values < 0.0001).

The results of generalized linear regression analyses were also shown in Table 3 . The age trends for PSV, EDV, and MFV were significantly negative while for RI and PI were significantly positive. The adjusted regression coefficients of PSV, EDV, MFV, RI, and PI per 5.0 years increase in age at enrollment were − 3.17 cm/sec, − 1.17 cm/sec, − 1.51 cm/sec, 0.0038, and 0.0079, respectively (all p -values < 0.005). As compared to female subjects, male subjects had significantly higher adjusted means for PSV, RI, and PI, while exhibiting significantly lower adjusted means for EDV and MFV (all p -values < 0.0001). After adjustment for the effects of age and sex, the effects of DM status on all five carotid hemodynamic parameters remained statistically significant. As compared to the non-DM controls, the adjusted means of PSV, EDV, and MFV were − 3.28 cm/sec ( p  = 0.0003), − 1.94 cm/sec ( p  < 0.0001), and − 2.38 cm/sec ( p  < 0.0001), respectively, lower for the DM cases. The age-sex-adjusted means of RI and PI of DM cases were 0.013 and 0.0061 (both p -values < 0.0001), respectively, higher than those of the non-DM controls.

Table 4 shows that the prevalence rates of DM were negatively correlated with increased levels of PSV, EDV, and MFV and were positively correlated with increased levels of RI and PI. The prevalence rates of DM for subjects whose carotid blood flows were of the lowest quartile (Q1) and the highest quartile (Q4) ranged from 14.1 to 17.5% and from 4.9 to 5.1%, respectively. The prevalence rates of DM for subjects who had Q1 levels of RI or PI were approximately 7.0% and for Q4 levels of RI or PI were approximately 16.0%. As compared to subjects who had Q1 levels of carotid blood flows, subjects who had Q4 levels of PSV, EDV, and MFV had significantly decreased ORs of having DM. The corresponding age-sex-adjusted ORs were 0.51 (95% CI 0.37–0.72), 0.37 (95% CI 0.26–0.54), and 0.40 (95% CI 0.28–0.57), respectively. The age-sex-adjusted ORs were significantly increased for subjects who had Q3 and Q4 levels of RI and PI as compared to those who had Q1 levels of RI and PI.

The results of multivariable analyses showed that the multivariable-adjusted ORs of having DM remained statistically significant for subjects who had Q4 levels of PSV, EDV, MFV, RI, and PI, relative to those with Q1 levels (Table 4 ). The corresponding multivariable-adjusted ORs of having DM were 0.59 (95% CI 0.41–0.83), 0.45 (95% CI 0.31–0.66), 0.53 (95% CI 0.37–0.77), 1.61 (95% CI 1.15–2.25), and 1.58 (95% CI 1.12–2.23), respectively. As compared to those who had a Q1 level of EDV, subjects who had a Q3 level of EDV also had a significantly lower OR (0.63; 95% CI 0.46–0.87). The multivariable-adjusted ORs of having DM per 5.0 cm/sec increase in PSV, EDV, and MFV were 0.95 (95% CI 0.92–0.98), 0.74 (95% CI 0.66–0.83), and 0.86 (95% CI 0.80–0.93), respectively. Increased PI and RI were significantly positively correlated with the likelihood of DM. The multivariable-adjusted ORs of having DM per 0.1 increases in RI was 1.52 (95% CI 1.21–1.91) and for per 1.0 increase in PI was 1.49 (95% CI 1.05–2.12).

The comparisons of the predictabilities of the regression models that contained different carotid hemodynamic parameters are shown in Table 5 . The AUROC for the basic model, i.e., the most predictive model selected from the regression analyses which contained all significantly conventional cardiovascular risk factors, was 0.7578 (95% CI 0.7346–0.7809). The results of multivariable logistic regression analyses showed that EDV was the most significantly independent predictor of DM. The AUROC were 0.7658 (95% CI 0.7430–0.7885) and 0.7678 (95% CI 0.7453–0.7904) for models adding EDV as a continuous or a categorical variable, respectively. The additions of PSV and MFV also significantly increased the predictabilities of DM status but with smaller added AUROC (Table 5 ).

To explore whether there were interactive effects between EDV and conventional CVD risk factors on the likelihoods of having DM, we carried out stratified analyses. Table 6 shows that increased EDV were correlated with significantly decreased ORs of having DM in all strata. The regression coefficient (SE) for per 5 cm/sec increase in EDV for subjects aged < 55 year was non-significantly different that of subjects aged ≥ 55 years (− 0.229 (0.096) vs. − 0.414 (0.069), p  = 0.12). Similarly, there was no significant difference in the regression coefficients between two strata of other factors.

In this study, we conducted a community-based case-control study, in which we enrolled approximately 4000 subjects aged 40–74 residing in the northern coastal area of Taiwan. In the case-control study, large numbers of DM cases and non-DM controls received color Doppler ultrasonographic measurements, including PSV, EDV, MFV, PI, and RI. We found significant age and sex effects on these hemodynamic parameters. After adjustment for the effects of age and sex, all these five carotid hemodynamic parameters remained significantly influenced by DM status. As compared to the non-DM controls, the adjusted means of PSV, EDV, and MFV were significantly lower and the adjusted means of RI and PI were significantly higher for the DM cases. We also found that after controlling for the effects of other conventional CVD risk factors, the multivariable-adjusted ORs of having DM were negatively correlated with PSV, EDV, and MFV and were positively correlated with PI and RI. More importantly, the additions of PSV, EDV, and MFV, either in categorical or continuous scales, significantly improved the predictabilities of the regression models on DM status and among them EDV was the most significantly independent predictor.

Pulsatility is a crucial aspect of the cardiovascular system, linked to artery elasticity. The natural pressure pulsations from each left ventricle contraction are reduced by the elasticity of large arteries. The aorta's expansion stores part of the stroke volume, lessening pulsatile stress on microvasculature 30 . However, with the loss of elastic fiber with age and disorders of metabolism, such as hyperlipidemia or DM, arterial walls continually increase their stiffness resulting in a gradual increase in blood pressure and, eventually affecting global cardiovascular health 16 . Pulsatile hemodynamics can be measured with invasive or non-invasive methods. Inserting an intraarterial catheter is the most accurate method of assessing pulsatile hemodynamics, however, multiple studies indicated that non-invasive methods could be reasonable surrogates for invasive ones 31 , 32 , 33 . Hemodynamic parameters including blood velocities such as PSV, EDV, and MFV as well as PI and RI were used to study their clinical correlation with different cardiovascular conditions including but not limited to stroke 34 , 35 , 36 , 37 , 38 , 39 , hypertension 40 , 41 , 42 , arterial stenosis 43 , 44 , 45 , 46 .

Prolonged hyperglycemia in patients with DM can damage the vascular endothelium leading to an increase in vascular stiffness and likely a change in hemodynamics 47 . The increase in the stiffness of large vessels can result in increased pulsation and microvascular complications 48 . Several studies have shown possible applications of hemodynamic parameters in predicting and preventing microvascular complications. In 2000, Lee et al. first studied 56 type 2 DM patients and 70 controls and measured their flow velocities and PI of the middle cerebral artery (MCA), extracranial internal carotid artery (ICA), and basilar artery (BA) 25 . They found that PIs of the MCA and ICA were closely correlated with the duration of DM. Some of these studies were lack of sex and age-matched controls 49 , 50 , 51 , 52 while some studies were designed to test the effect of drugs with only DM patients 53 , 54 . In studies with sex and age-matched controls, Agha et al. measured the velocity and PI of BA, ICA, and MCA in 141 DM patients and 132 controls 55 ; Dikanovic et al. measured the velocity and PI of MCA in 100 type 2 DM patients and 100 controls 26 ; Park et al. measured the velocity and PI of MCA in 90 type 2 DM patients and 45 controls 56 ; Zou et al. measured the velocity, PI and RI of dorsalis pedis artery and plantar digital artery in 56 type 2 DM patients and 50 controls 57 . All of these studies came to the same conclusion as we did that hemodynamic parameters including velocities, PI, and RI can be useful indicators and predictors of DM. However, none of them perform their studies at the same large scale as we did.

In a previous study, we included 4073 participants from the same study area, with prevalence rates of carotid plaque and DM at 35.4% and 11.3%, respectively 22 . The study found statistically significant linear trends between the likelihood of having DM and the total number of carotid plaques, maximum carotid stenosis, or severity of carotid atherosclerosis. The multivariate-adjusted odds ratio (OR) for DM was 1.57 (1.25–1.98), indicating a significantly higher risk for subjects with carotid plaques compared to those without observable plaque images. Furthermore, a greater number of carotid plaques, increased maximum carotid atherosclerosis, and more severe carotid atherosclerosis were associated with significantly higher ORs for DM. The prevalence rate of carotid plaque in the prevalent DM group was also significantly higher than in the incident DM group. In our most recent case-control study, we enrolled 309 carotid plaque-positive subjects and 439 carotid plaque-negative subjects from a community-based cohort 23 . Multivariable analyses of anthropometric attributes and biochemical profiles revealed that DM was a significant independent predictor in the best-fit regression model for the presence of carotid plaque. Among the 43 tested DM SNPs, 9 showed promising associations with carotid atherosclerosis, controlling for age, cigarette smoking, and hypertension. Although not all of these promising SNPs demonstrated significant independent effects in the multivariable analyses, a notable linear trend between their composite indicator 9-GCS and the risks of carotid atherosclerosis was observed. We identified four SNPs (rs9937354, rs10842993, rs7180016, and rs4383154) that exhibited significant independent effects with carotid atherosclerosis. Genes that are closely associated with these SNPs include FTO, PRC1, GP2, and KLHL42.

Several potential mechanisms of increased arterial stiffness and altered hemodynamics in DM have been implicated including the formation of advanced glycation endproducts (AGEs) and the dysregulation of nitric oxide (NO) 58 . The formation of AGE involves multiple reversible and irreversible steps, ultimately leading to the pathological binding of collagen molecules within the arterial vessel wall 59 . Numerous studies have linked AGEs to the acceleration of age-related vascular changes and the development of cardiovascular events in both diabetic and non-diabetic populations 60 . The presence of AGE-induced cross-links can make collagen highly resistant to enzymatic breakdown, resulting in a reduced degradation rate. This, in turn, contributes to the increased collagen content observed in arterial walls, which is a characteristic of aging and is further accelerated in conditions such as DM 61 . Research has shown a positive correlation between carotid-femoral pulse wave velocity and collagen crosslinking 62 . Moreover, the levels of specific AGEs in aortic tissue have been found to correlate with aortic stiffness in individuals with and without DM 63 . NO possesses various beneficial properties, including vasodilation, anti-platelet activity, anti-inflammatory effects, and antioxidant properties 64 . However, in the state of insulin resistance, the activation of NO synthase is impaired, and there is an increase in the production of superoxide. These factors together contribute to a decrease in the availability of NO 65 . In individuals with diabetes, particularly those with microvascular disease, basal levels of NO are reduced compared to those without such complications. Furthermore, the severity of microvascular disease correlates with a further decline in NO levels 66 . Further mechanical studies including gene-association studies based on our current findings will provide insight into finding therapeutic targets for atherosclerosis and related complications in DM patients.

The findings of this study highlight a noteworthy association between DM and changes in hemodynamic parameters. Adding hemodynamic parameters enhanced the predictabilities of the regression models on DM status. Gaining a deeper understanding of this relationship can aid in identifying individuals who are at a heightened risk of DM. Future follow-up and mechanical studies will enlighten us on factors that contribute to the development of vascular complications in DM patients.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Abbreviations

Area under the receiver operating curve

Body mass index

Common carotid artery

Coronary heart disease

Total cholesterol

Confidence interval

Diastolic blood pressure

• Diabetes mellitus

End-diastolic velocity

Fasting plasma glucose

Fasting triglycerides

High-density lipoprotein cholesterol

Hip circumference

Low-density lipoprotein cholesterol

Mean blood flow velocity

• Pulsatility index

Peak systolic velocity

• Resistance index

Systolic blood pressure

Standard deviation

Standard error

Waist circumference

Waist-to-hip ratio

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Acknowledgements

We thank the staff in the district health station of Tamsui District, Sanzhi District, and Shimen District, New Taipei City, for their administrative support.

This work was supported by research grants from the Council of Science and Technology of Taiwan (MOST 111-2314-B-715-007 & NSTC 112-2314-B-715-007-MY3) and MacKay Medical College (MMC-RD-110-1B-P010 & MMC-RD-111-1B-P007). The funding agencies played no role in the research.

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Tzu-Wei Wu, Yih-Jer Wu, Chao-Liang Chou & Li-Yu Wang

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Cardiovascular Center, Department of Internal Medicine, MacKay Memorial Hospital, Taipei, Taiwan

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Department of Neurology, MacKay Memorial Hospital, New Taipei City, Taiwan

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T.W.W. developed the study design, analyzed and interpreted data, and wrote the manuscript. Y.J.W. interpreted the results, contributed to the discussion, and revised the manuscript. C.L.C., C.F.C., and S.X.L. contributed to the study design, interpreted results, and discussion. L.Y.W. developed the study design, analyzed data, interpreted data, wrote the manuscript, and revised the manuscript. All authors read and approved the final manuscript.

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Wu, TW., Wu, YJ., Chou, CL. et al. Hemodynamic parameters and diabetes mellitus in community-dwelling middle-aged adults and elders: a community-based study. Sci Rep 14 , 12032 (2024). https://doi.org/10.1038/s41598-024-62866-7

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In the tech world and beyond, new 5G applications are being discovered every day. From driverless cars to smarter cities, farms, and even shopping experiences, the latest standard in wireless networks is poised to transform the way we interact with information, devices and each other. What better time to take a closer look at how humans are putting 5G to use to transform their world.

What is 5G?

5G (fifth-generation mobile technology  is the newest standard for cellular networks. Like its predecessors, 3G, 4G and 4G LTE, 5G technology uses radio waves for data transmission. However, due to significant improvements in latency, throughput and bandwidth, 5G is capable of faster download and upload speeds than previous networks.

Since its release in 2019, 5G broadband technology has been hailed as a breakthrough technology with significant implications for both consumers and businesses. Primarily, this is due to its ability to handle large volumes of data that is generated by complex devices that use its networks.

As mobile technology has expanded over the years, the number of data users generate every day has increased exponentially. Currently, other transformational technologies like  artificial intelligence (AI),  the  Internet of Things (IoT ) and  machine learning (ML)  require faster speeds to function than 3G and 4G networks offer. Enter 5G, with its lightning-fast data transfer capabilities that allow newer technologies to function in the way they were designed to.

Here are some of the biggest differences between 5G and previous wireless networks.

• Physical footprint : The transmitters that are used in 5G technology are smaller than in predecessors’ networks, allowing for discrete placement in out-of-the-way places. Furthermore, “cells”—geographical areas that all wireless networks require for connectivity—in 5G networks are smaller and require less power to run than in previous generations.
• Error rates : 5G’s adaptive Modulation and Coding Scheme (MCS), a schematic that wifi devices use to transmit data, is more powerful than ones in 3G and 4G networks. This makes 5G’s Block Error Rate (BER)—a metric of error frequency—much lower. 
• Bandwidth : By using a broader spectrum of radio frequencies than previous wireless networks, 5G networks can transmit on a wider range of bandwidths. This increases the number of devices that they can support at any given time.
• Lower latency : 5G’s low  latency , a measurement of the time it takes data to travel from one location to another, is a significant upgrade over previous generations. This means that routine activities like downloading a file or working in the cloud is going to be faster with a 5G connection than a connection on a different network.

Like all wireless networks, 5G networks are separated into geographical areas that are known as cells. Within each cell, wireless devices—such as smartphones, PCs, and IoT devices—connect to the internet via radio waves that are transmitted between an antenna and a base station. The technology that underpins 5G is essentially the same as in 3G and 4G networks. But due to its lower latency, 5G networks are capable of delivering faster download speeds—in some cases as high as 10 gigabits per second (Gbps).

As more and more devices are built for 5G speeds, demand for 5G connectivity is growing. Today, many popular Internet Service Providers (ISPs), such as Verizon, Google and AT&T, offer 5G networks to homes and businesses. According to Statista,  more than 200 million homes  and businesses have already purchased it with that number expected to at least double by 2028 (link resides outside ibm.com).

Let’s take a look at three areas of technological improvement that have made 5G so unique.

New telecom specifications

The 5G NR (New Radio) standard for cellular networks defines a new radio access technology (RAT) specification for all 5G mobile networks. The 5G rollout began in 2018 with a global initiative known as the 3rd Generation Partnership Project (3FPP). The initiative defined a new set of standards to steer the design of devices and applications for use on 5G networks.

The initiative was a success, and 5G networks grew swiftly in the ensuing years. Today, 45% of networks worldwide are 5G compatible, with that number forecasted to rise to 85% by the end of the decade according to  a recent report by Ericsson  (link resides outside ibm.com).

Independent virtual networks (network slicing)

On 5G networks, network operators can offer multiple independent virtual networks (in addition to public ones) on the same infrastructure. Unlike previous wireless networks, this new capability allows users to do more things remotely with greater security than ever before. For example, on a 5G network, enterprises can create use cases or business models and assign them their own independent virtual network. This dramatically improves the user experience for their employees by adding greater customizability and security.

Private networks

In addition to network slicing, creating a 5G private network can also enhance personalization and security features over those available on previous generations of wireless networks. Global businesses seeking more control and mobility for their employees increasingly turn to private 5G network architectures rather than public networks they’ve used in the past.

Now that we better understand how 5G technology works, let’s take a closer look at some of the exciting applications it’s enabling.

Autonomous vehicles

From taxi cabs to drones and beyond, 5G technology underpins most of the next-generation capabilities in autonomous vehicles. Until the 5G cellular standard came along, fully autonomous vehicles were a bit of a pipe dream due to the data transmission limitations of 3G and 4G technology. Now, 5G’s lightning-fast connection speeds have made transport systems for cars, trains and more, faster than previous generations, transforming the way systems and devices connect, communicate and collaborate.

Smart factories

5G, along with AI and ML, is poised to help factories become not only smarter but more automated, efficient, and resilient. Today, many mundane but necessary tasks that are associated with equipment repair and optimization are being turned over to machines thanks to 5G connectivity paired with AI and ML capabilities. This is one area where 5G is expected to be highly disruptive, impacting everything from fuel economy to the design of equipment lifecycles and how goods arrive at our homes.

For example, on a busy factory floor, drones and cameras that are connected to smart devices that use the IoT can help locate and transport something more efficiently than in the past and prevent theft. Not only is this better for the environment and consumers, but it also frees up employees to dedicate their time and energy to tasks that are more suited to their skill sets.

Smart cities

The idea of a hyper-connected urban environment that uses 5G network speeds to spur innovation in areas like law enforcement, waste disposal and disaster mitigation is fast becoming a reality. Some cities already use 5G-enabled sensors to track traffic patterns in real time and adjust signals, helping guide the flow of traffic, minimize congestion, and improve air quality.

In another example, 5G power grids monitor supply and demand across heavily populated areas and deploy AI and ML applications to “learn” what times energy is in high or low demand. This process has been shown to significantly impact energy conservation and waste, potentially reducing carbon emissions and helping cities reach sustainability goals.

Smart healthcare

Hospitals, doctors, and the healthcare industry as a whole already benefit from the speed and reliability of 5G networks every day. One example is the area of remote surgery that uses robotics and a high-definition live stream that is connected to the internet via a 5G network. Another is the field of mobile health, where 5G gives medical workers in the field quick access to patient data and medical history. This enables them to make smarter decisions, faster, and potentially save lives.

Lastly, as we saw during the pandemic, contact tracing and the mapping of outbreaks are critical to keeping populations safe. 5G’s ability to deliver of volumes of data swiftly and securely allows experts to make more informed decisions that have ramifications for everyone.

5G paired with new technological capabilities won’t just result in the automation of employee tasks, it will dramatically improve them and the overall  employee experience . Take virtual reality (VR) and augmented reality (AR), for example. VR (digital environments that shut out the real world) and AR (digital content that augments the real world) are already used by stockroom employees, transportation drivers and many others. These employees rely on wearables that are connected to a 5G network capable of high-speed data transfer rates that improve several key capabilities, including the following:

• Live views : 5G connectivity provides live, real-time views of equipment, events, and even people. One way in which this feature is being used in professional sports is to allow broadcasters to remotely call a sporting event from outside the stadium where the event is taking place.
• Digital overlays : IoT applications in a warehouse or industrial setting allow workers that are equipped with smart glasses (or even just a smartphone) to obtain real-time insights from an application. This includes repair instructions or the name and location of a spare part.
• Drone inspections : Right now, one of the leading causes of employee injury is inspection of equipment or project sites in remote and potentially dangerous areas. Drones, which are connected via 5G networks, can safely monitor equipment and project sites and even take readings from hard-to-reach gauges.

Edge computing , a computing framework that allows computations to be done closer to data sources, is fast becoming the standard for enterprises. According to  this Gartner white paper  (link resides outside ibm.com), by 2025, 75% of enterprise data will be processed at the edge (compared to only 10% today). This shift saves businesses time and money and enables better control over large volumes of data. It would be impossible without the new speed standards that are generated by 5G technology. 

Ultra-reliable edge computing and 5G enable the enterprise to achieve faster transmission speeds, increased control and greater security over massive volumes of data. Together, these twin technologies will help reduce latency while increasing speed, reliability and bandwidth, resulting in faster, more comprehensive data analysis and insights for businesses everywhere.

5G solutions with IBM Cloud Satellite  

5G presents significant opportunities for the enterprise, but first, you need a platform that can handle its speed. IBM Cloud Satellite® lets you deploy and run apps consistently across on-premises, edge computing and public cloud environments on a 5G network. And it’s all enabled by secure and auditable communications within the IBM Cloud®.

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Outbreak of Human Trichinellosis — Arizona, Minnesota, and South Dakota, 2022

Weekly / May 23, 2024 / 73(20);456–459

Shama Cash-Goldwasser, MD 1 ; Dustin Ortbahn, MPH 2 ; Muthu Narayan, DO 3 ; Conor Fitzgerald, MPH 4 ; Keila Maldonado 5 ; James Currie, MD 6 ; Anne Straily, DVM 7 ; Sarah Sapp, PhD 7 ; Henry S. Bishop 7 ; Billy Watson, PhD 7 ; Margaret Neja 7 ; Yvonne Qvarnstrom, PhD 7 ; David M. Berman, DO 8 ; Sarah Y. Park, MD 8 ; Kirk Smith, DVM, PhD 9 ; Stacy Holzbauer, DVM 9 ,10 ( View author affiliations )

What is already known about this topic?

Human trichinellosis cases in the United States are rare and are usually acquired through consumption of wild game.

What is added by this report?

Among eight persons who shared a meal that included the meat of a black bear harvested in Canada and frozen for 45 days, six trichinellosis cases were identified. The meat was grilled with vegetables and served rare; two cases occurred in persons who ate only the vegetables. Motile freeze-resistant Trichinella nativa larvae were identified in remaining meat frozen for >15 weeks.

What are the implications for public health practice?

Cooking meat to an internal temperature of ≥165°F (≥74°C) is necessary to kill Trichinella spp. parasites. Trichinella -infected meat can cross-contaminate other foods, and raw meat should be kept and prepared separate from other foods to prevent cross-contamination.

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Trichinellosis is a parasitic zoonotic disease transmitted through the consumption of meat from animals infected with Trichinella spp. nematodes. In North America, human trichinellosis is rare and is most commonly acquired through consumption of wild game meat. In July 2022, a hospitalized patient with suspected trichinellosis was reported to the Minnesota Department of Health. One week before symptom onset, the patient and eight other persons shared a meal that included bear meat that had been frozen for 45 days before being grilled and served rare with vegetables that had been cooked with the meat. Investigation identified six trichinellosis cases, including two in persons who consumed only the vegetables. Motile Trichinella larvae were found in remaining bear meat that had been frozen for >15 weeks. Molecular testing identified larvae from the bear meat as Trichinella nativa , a freeze-resistant species. Persons who consume meat from wild game animals should be aware that that adequate cooking is the only reliable way to kill Trichinella parasites and that infected meat can cross-contaminate other foods.

Investigation and Results

Index patient notification.

In July 2022, the Minnesota Department of Health was notified of a man aged 29 years who was hospitalized with fever, severe myalgias, periorbital edema, eosinophilia, and other laboratory abnormalities ( Table ); health care providers suspected trichinellosis. The patient had sought care for his symptoms, which commenced in early July, four times and had been hospitalized twice over a 17-day period. During his second hospitalization, providers obtained a history of bear meat consumption, and empiric albendazole treatment for probable trichinellosis was initiated. An investigation was launched to confirm the diagnosis, identify additional cases, and ascertain the source of infection to prevent future cases. The index patient’s diagnosis was confirmed by a positive Trichinella immunoglobulin (Ig) G antibody test result.

Potential Exposure Source Identification

Six days before symptom onset in the index patient, he and eight extended family members from three states (Arizona, Minnesota, and South Dakota) had gathered for several days in South Dakota and shared a meal that included kabobs made from the meat of a black bear ( Ursus americanus ), which had been harvested by one of the family members in northern Saskatchewan, Canada in May 2022. The hunting outfitter had recommended freezing the meat to kill parasites. The meat was frozen in a household freezer* for 45 days until being thawed and grilled with vegetables. The meat was initially inadvertently served rare, reportedly because the meat was dark in color, and it was difficult for the family members to visually ascertain the level of doneness. After some of the family members began eating the meat and noticed that it was undercooked, the meat was recooked before being served again. The family reunion concluded before onset of illness in the index patient.

Laboratory Investigation and Case Definition

Public health authorities in Arizona, Minnesota, and South Dakota interviewed eight of the nine persons who had attended the implicated meal. The ninth attendee was a person aged <18 years whose exposure status could not be confirmed; however, that person reportedly remained healthy. Testing of paired acute and convalescent sera for Trichinella IgG antibodies was recommended for the eight exposed persons and was completed for six. Pathogen-agnostic microbial cell-free metagenomic DNA sequencing ( 1 ) was performed on plasma samples from the index patient and one other person who had sought care twice before being hospitalized with fever, myalgias, abdominal pain, periorbital edema, and laboratory abnormalities. Trichinellosis cases were classified according to the 2014 case definition from the Council for State and Territorial Epidemiologists (CSTE), † (i.e., the presence of clinically compatible symptoms in a person who had consumed an epidemiologically implicated meal or meat in which the parasite was demonstrated [probable] or had a positive serologic test result for Trichinella antibodies [confirmed]). Samples of frozen bear meat were obtained from the household freezer and sent to CDC for artificial tissue digestion and microscopic examination for larvae and molecular testing for Trichinella spp.

Additional Case Detection and Exposure Source Confirmation

Among the eight interviewed persons, five consumed the bear meat, and eight consumed the vegetables that had been cooked with it. Six of the eight persons who attended the meal, including four who consumed the bear meat and the vegetables, and two who consumed only the vegetables (but no meat), had symptoms consistent with trichinellosis, and met case criteria (two confirmed and four probable). Patients with trichinellosis ranged in age from 12 to 62 years and lived in three states: Arizona (one), Minnesota (four), and South Dakota (one). All cases were diagnosed in the patients’ state of residence. Three of the six symptomatic persons, two of whom sought care at least twice before being offered treatment, were hospitalized. The three hospitalized persons received trichinellosis-directed treatment with albendazole. § All six symptomatic persons recovered; the nonhospitalized patients did not receive trichinellosis-directed treatment because their symptoms had resolved with supportive care only, and the benefit of treatment after larval invasion of muscle is unclear ( 2 ). Six persons submitted a serum sample, each collected within 4 weeks of symptom onset; two specimens tested positive for Trichinella IgG antibodies by enzyme-linked immunosorbent assay. Two persons submitted a plasma sample for microbial cell-free DNA sequencing during hospitalization for trichinellosis-compatible symptoms, and both plasma samples tested positive for Trichinella spp. DNA. Microscopy identified motile Trichinella larvae (>800 larvae/g) in samples of bear meat that had been frozen for 110 days in a household freezer ( Figure ). Real-time multiplex polymerase chain reaction testing ( 3 ) of the bear meat was positive for T. nativa and whole genome sequencing identified mitochondrial sequences 100% identical to T. nativa.

Public Health Response

The family member who harvested the bear and provided meat samples for testing was advised to discard any remaining meat. All identified trichinellosis cases were reported to appropriate state health departments and to CDC. CDC notified the Public Health Agency of Canada of the outbreak and the confirmed source of infection. This activity was reviewed by CDC, deemed not research, and was conducted consistent with applicable federal law and CDC policy. ¶

Trichinellosis is rarely reported in the United States. As a result of changes in pork production practices from historical norms that fostered transmission, most cases reported in recent years are attributed to consumption of meat from wild game ( 4 ). During January 2016–December 2022, seven U.S. trichinellosis outbreaks, including 35 probable and confirmed cases, were reported to CDC; bear meat was the suspected or confirmed source of infection in the majority of those outbreaks (CDC, unpublished data, 2022). Estimates of Trichinella infection prevalence among wild animal host species vary widely. A Trichinella infection prevalence range of at least 1% to 24% among black bears in Canada and Alaska has been reported, and even higher prevalences of Trichinella infection are reported among species of predators that are strict carnivores (e.g., polar bear, wolverine, and cougar) ( 5 ). The frequency with which black bear meat is the implicated source of human infection might be driven by hunting practices, ecological factors, and the relatively high parasite density observed in the muscle of infected black bears compared with that of other species ( 6 , 7 ).

Because symptoms of trichinellosis are typically nonspecific, diagnosis of infection requires a high index of suspicion; however, periorbital edema and certain laboratory abnormalities (e.g., eosinophilia and elevated creatine kinase levels) can provide etiologic clues. In this outbreak, two of the hospitalized patients sought care multiple times before receiving a diagnosis. Four of the six patients met clinical and epidemiologic criteria and thus were considered probable cases. Laboratory confirmation can be challenging because of the limited sensitivity of antibody testing early in illness ( 8 ); in this investigation, acute Trichinella IgG test results were positive in only two of six tested patient specimens. The clinical utility of trichinellosis test results obtained after acute illness is limited, and historically, public health investigators have had difficulty obtaining convalescent serum samples from persons who have recovered. Laboratory criteria in the current CSTE trichinellosis case definition do not include nucleic acid testing of human specimens. The sensitivity of such assays to detect Trichinella DNA in blood is uncharacterized; however, plasma samples from both patients tested by metagenomic sequencing ( 1 ) yielded positive results for Trichinella DNA. As demonstrated in this outbreak, pathogen-agnostic molecular assays can be useful for detection of rare diseases when standard workup is unrevealing and if other diagnostic tests lack sensitivity.

Implications for Public Health Practice

Although freezing kills Trichinella species commonly implicated in pork-associated outbreaks, freeze-resistant Trichinella species, including T. nativa and the T6 genotype ( 9 ), predominate in Arctic and sub-Arctic regions ( 6 ). Larval motility was observed in bear meat that had been frozen for nearly 4 months (110 days). Persons who consume game meat, especially that harvested in northern latitudes, should be informed that adequate cooking is the only reliable way to kill Trichinella parasites. Cooking wild game meat to an internal temperature of ≥165°F (≥74°C) is recommended by public health authorities**; temperatures should be verified with a meat thermometer. As demonstrated in this outbreak, the color of meat is not a good indicator of cooking adequacy. Safe handling of raw meat (i.e., separating raw or undercooked meat and its juices from other foods) is recommended to prevent trichinellosis; this investigation and previous investigations suggest that Trichinella -infected meat can cross-contaminate other foods ( 10 ). Government and private entities that oversee and organize hunting should educate hunters about these risks and effective preventative measures.

Acknowledgments

The persons affected by this outbreak; Lauren Ahart, Sue Montgomery, Parasitic Diseases Branch, CDC.

Corresponding author: Shama Cash-Goldwasser, [email protected] .

1 Epidemic Intelligence Service, CDC; 2 South Dakota Department of Health; 3 University of Minnesota, Minneapolis, Minnesota; 4 Arizona Department of Health Services; 5 Maricopa County Department of Public Health, Phoenix, Arizona; 6 Lakeview Clinic, Waconia, Minnesota; 7 Division of Parasitic Diseases and Malaria, Center for Global Health, CDC; 8 Medical Affairs, Karius, Inc., Redwood City, California; 9 Minnesota Department of Health; 10 Division of State and Local Readiness, Center for Preparedness and Response, CDC.

All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. David M. Berman reports that he is a paid laboratory medical consultant for Precision Health Solutions and reports ownership of company shares in Karius, Inc. No other potential conflicts of interest were disclosed.

* The temperature of the freezer is not known.

† https://ndc.services.cdc.gov/case-definitions/trichinellosis-2014/

§ https://www.cdc.gov/trichinellosis/hcp/clinical-care/index.html

¶ 45 C.F.R. part 46, 21 C.F.R. part 56; 42 U.S.C. Sect. 241(d); 5 U.S.C. Sect. 552a; 44 U.S.C. Sect. 3501 et seq.

** https://www.cdc.gov/trichinellosis/prevention/index.html

• Blauwkamp TA, Thair S, Rosen MJ, et al. Analytical and clinical validation of a microbial cell-free DNA sequencing test for infectious disease. Nat Microbiol 2019;4:663–74. https://doi.org/10.1038/s41564-018-0349-6 PMID:30742071
• Pozio E, Sacchini D, Sacchi L, Tamburrini A, Alberici F. Failure of mebendazole in the treatment of humans with Trichinella spiralis infection at the stage of encapsulating larvae. Clin Infect Dis 2001;32:638–42. https://doi.org/10.1086/318707 PMID:11181129
• Almeida M, Bishop H, Nascimento FS, Mathison B, Bradbury RS, Silva AD. Multiplex TaqMan qPCR assay for specific identification of encapsulated Trichinella species prevalent in North America. Mem Inst Oswaldo Cruz 2018;113:e180305. https://doi.org/10.1590/0074-02760180305 PMID:30379199
• Wilson NO, Hall RL, Montgomery SP, Jones JL. Trichinellosis surveillance—United States, 2008-2012. MMWR Surveill Summ 2015;64(No. SS-1):1–8. PMID:25590865
• Oksanen A, Kärssin A, Berg RPKD, et al. Epidemiology of Trichinella in the Arctic and subarctic: a review. Food Waterborne Parasitol 2022;28:e00167. https://doi.org/10.1016/j.fawpar.2022.e00167 PMID:35812081
• Gajadhar AA, Forbes LB. A 10-year wildlife survey of 15 species of Canadian carnivores identifies new hosts or geographic locations for Trichinella genotypes T2, T4, T5, and T6. Vet Parasitol 2010;168:78–83. https://doi.org/10.1016/j.vetpar.2009.10.012 PMID:19926223
• Harms NJ, Larivee M, Scandrett B, Russell D. High prevalence and intensity of Trichinella infection in Yukon American Black ( Ursus americanus ) and Grizzly ( Ursus arctos ) bears. J Wildl Dis 2021;57:429–33. https://doi.org/10.7589/JWD-D-20-00135 PMID:33822166
• Yang Y, Cai YN, Tong MW, et al. Serological tools for detection of Trichinella infection in animals and humans. One Health 2016;2:25–30. https://doi.org/10.1016/j.onehlt.2015.11.005 PMID:28616474
• Pozio E. Adaptation of Trichinella spp. for survival in cold climates. Food Waterborne Parasitol 2016;4:4–12. https://doi.org/10.1016/j.fawpar.2016.07.001
• Hall RL, Lindsay A, Hammond C, et al. Outbreak of human trichinellosis in Northern California caused by Trichinella murrelli . Am J Trop Med Hyg 2012;87:297–302. https://doi.org/10.4269/ajtmh.2012.12-0075 PMID:22855761

Abbreviations: eos = eosinophils; F = female; M = male; NA = not applicable; ND = not done; WBC = white blood cell. * Initial results are from hospitalization during which trichinellosis was suspected. Reference ranges varied among different laboratories that conducted testing. † Reference range = 4–88. § Reference range = 39–208. ¶ Consumed vegetables that were cooked and served with the bear meat. ** Reference range = 39–308.

FIGURE . Microscopic examination of encapsulated larvae in a direct black bear meat muscle squash prep (A), larvae liberated from artificially digested bear meat (B), and motile larvae viewed with differential interference contrast microscopy (C and D)* from black bear meat suspected as the source of an outbreak of human Trichinella nativa infections — Arizona, Minnesota, and South Dakota, 2022

Photos/Division of Parasitic Diseases and Malaria, Center for Global Health, CDC

* Scale bars = 100 µ m.

Suggested citation for this article: Cash-Goldwasser S, Ortbahn D, Narayan M, et al. Outbreak of Human Trichinellosis — Arizona, Minnesota, and South Dakota, 2022. MMWR Morb Mortal Wkly Rep 2024;73:456–459. DOI: http://dx.doi.org/10.15585/mmwr.mm7320a2 .

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Duke settlement could mean less drastic price hikes in rate case, affordability study

Duke Energy and six other parties filed a settlement agreement Friday regarding Duke’s controversial residential electric rate increase case.

The settlement could lessen the proposed monthly rate hike for customers beginning in August and establish a Low-Income Affordability Working Group to create more programs to assist customers.

Last night, Duke and the Public Service Commission (PSC), which regulates utilities in the state, heard from customers for the final time before the PSC decides Duke’s case.

In January, Duke requested a two-part cost hike for residential electric rates that would increase costs by nearly 20%. They faced criticism from customers in the Upstate , who voiced concerns about how the cost would impact them.

Duke initially requested $323 million in increased revenue. In the settlement, they lessened the request to $240 million, a decrease of about 26%.

If the PSC adopts the settlement, a customer using 1,000 kilowatt hours each month would see an increase of about $12.53 each month beginning in August 2024 and $6.42 each month starting in August 2026.

The initial application would have cost the same customer about $5 more in 2024 and $4 more in 2026.

The South Carolina Office of Regulatory Staff, the South Carolina Energy Users Committee, the Southern Alliance for Clean Energy, the Coastal Conservation League, Vote Solar and the South Carolina Small Business Chamber of Commerce joined Duke Energy Carolinas in the settlement agreement.

Walmart and CEC Recycling did not sign the settlement agreement but noted that neither company opposed it. However, the South Carolina Department of Consumer Affairs did not support the settlement.

On Monday morning, representatives from the company and other settling parties met for a merits hearing.Because the new settlement, which is 51 pages long, was filed on Friday, the PSC and involved parties are still “trying to parse through everything,” said PSC Chair Florence P. Belser.

Consequently, Belser recessed Monday’s hearing, which will resume on Thursday, May 23, at 9 a.m. to give everyone involved more time to review the settlement.

“I'm not trying to drag this out,” Belser said. “I just want all parties and the commission to have the opportunity to be as familiar as possible with the settlement agreement and with other testimony that's before the commission.”

During Monday’s hearing, Duke’s Deputy General Counsel Camal O. Robinson said the company agreed to reduce overall revenue costs.

“The settlement specifically provides for a 26% lower revenue impact than that requested by the company, and also provides that the company will make a $2 million shareholder contribution to fund a Low-Income Affordability Study in South Carolina and low-income weatherization programs,” Robinson said.

The $2 million will come from shareholders, Robinson said, rather than customers.

According to the settlement, $1 million will go to weatherization programs , or programs that help reduce energy consumption. An example of weatherization is upgrading insulation or adding moisture control to a home.

The other $1 million will go to a study modeled after a similar Duke program in North Carolina to evaluate energy consumption for lower-income customers. The study will be completed by the end of 2025. The company claimed it would evaluate current programs and search for additional protection for customers struggling to afford their electric bills.

Duke also promised to improve their Residential Neighborhood Energy Savings program (NES).

While several parties agreed, the S.C. Department of Consumer Affairs said they could not find common ground with the company, Advocacy Director and Deputy Consumer Advocate Roger Hall said.

“The Department of Consumer Affairs did engage in good faith negotiations with all the parties in this matter. Our aim and any negotiations or any hearing is to get the best deal possible for residential customers while recognizing the needs of the other customer classes and any other interest groups,” Hall said. “Unfortunately, we were just not able to get there in this matter.”

The PSC held its final hearing for customers last night. Duke, the PSC, and the other parties involved in the settlement will meet at the next hearing on Thursday. After the hearings, the PSC will decide whether to adopt the settlement.

Sarah Swetlik covers climate change and environmental issues in South Carolina's Upstate for The Greenville News.   Reach her at [email protected] or on X at @sarahgswetlik .

Have a question for Sustainability with Sarah? Ask  here  or email [email protected] .

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• The pEGASUS-HPC stent system for intracranial arterial stenosis: a single-center case series
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• http://orcid.org/0000-0003-2725-7685 Daniel Pielenz 1 ,
• Joachim Klisch 1 , 2 ,
• http://orcid.org/0000-0002-2677-8780 David Fiorella 3 ,
• Matthias Gawlitza 4 ,
• Andreas Steinbrecher 5 ,
• Elke Leinisch 5 ,
• Elmar Lobsien 5 ,
• Karl-Titus Hoffmann 4 ,
• http://orcid.org/0000-0002-3936-0981 Donald Lobsien 1
• 1 Department of Neuroradiology , Helios Hospital Erfurt , Erfurt , Thüringen , Germany
• 2 Department of Neuroradiology , Helios Vogtland Hospital Plauen , Plauen , Sachsen , Germany
• 3 Department of Neurosurgery , Stony Brook University , Stony Brook , New York , USA
• 4 University Hospital Leipzig Institute for Neuroradiology , Leipzig , Sachsen , Germany
• 5 Department of Neurology , Helios Hospital Erfurt , Erfurt , Thüringen , Germany
• Correspondence to Daniel Pielenz, Neuroradiology, Helios Hospital Erfurt, Erfurt, Thüringen, Germany; daniel.pielenz{at}helios-gesundheit.de

Background Intracranial arterial stenting is a technique for the treatment of symptomatic stenosis. In this single-center retrospective case series we evaluated a novel low profile laser-cut stent with an antithrombogenic hydrophilic polymer coating (pEGASUS-HPC, Phenox GmbH, Bochum, Germany) for the treatment of intracranial stenosis in the setting of acute ischemic stroke and elective cases.

Methods All patients treated with pEGASUS-HPC for one or more intracranial arterial stenoses at our institution were retrospectively included. Clinical, imaging and procedural parameters as well as clinical and imaging follow-up data were collected.

Results We performed 43 interventions in 41 patients with 42 stenoses in our neurovascular center between August 2021 and February 2024. Twenty-one patients (51.2%) were female and the mean±SD age was 71±10.8 years. Thirty-seven (86.1%) procedures were performed in the setting of endovascular acute ischemic stroke treatment. Technical or procedural complications occurred in seven patients (16.3%), six in the thrombectomy group and one in the elective group. One stent-related hemorrhagic complication (subarachnoid hemorrhage) occurred in emergency cases and symptomatic intracerebral hemorrhage occurred in one patient treated in an elective setting. Overall stenosis reduction following pEGASUS-HPC stent implantation was 53.0±18.0%. On follow-up imaging, which was available for 16 patients (37.2%) after an average of 32±58.6 days, 62.5% of the stents were patent.

Conclusion Our single-center case series demonstrates the feasibility of using the pEGASUS-HPC stent system, especially in emergency situations when thrombectomy fails.

• angiography
• atherosclerosis

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

https://doi.org/10.1136/jnis-2024-021737

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WHAT IS ALREADY KNOWN ON THIS TOPIC

Intracranial arterial stenting for the treatment of symptomatic intracranial stenoses is controversial but emerges as a valuable option in the setting of acute stroke thrombectomy. The pEGASUS-HPC is a novel laser-cut self-expandable stent with antithrombogenic polymer coating, potentially reducing the risk of local thrombotic complications.

WHAT THIS STUDY ADDS

In our study, the novel pEGASUS-HPC stent showed a high level of procedural effectiveness.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

Bail-out stenting using this stent in failed thrombectomy cases is a valuable treatment option as well as treatment of intracranial stenosis with recurrent symptoms under best medical treatment.

Introduction

Intracranial arterial stenosis poses a significant challenge in the treatment of acute ischemic stroke. While stenting is mostly used as a secondary therapy in elective cases after exhausting best medical treatment options, it remains a subject of ongoing debate as a bail-out therapy in acute stroke recanalization. Emerging data suggest potential benefits for ‘rescue’ or ‘bail-out stenting’ in certain acute cases. 1–4 The pEGASUS-HPC stent (Phenox GmbH, Bochum, Germany) is a novel low-profile, self-expanding laser-cut stent designed for intracranial aneurysm and stenosis treatment. It is available with the HPC coating that reduces thrombogenicity. 5

We present a retrospective single-center series documenting our initial experience with the pEGASUS-HPC stent system for the treatment of intracranial arterial stenosis in both emergency and elective settings.

Materials and methods

Study design.

The database of our neurovascular center was retrospectively screened and all patients and procedures fulfilling the following criteria were included in the study:

Patients (age ≥18 years) treated with the pEGASUS-HPC stent for intracranial arterial stenosis.

Conditions potentially leading to a luminal stenosis (ie, atherosclerotic, dissection, wall-adherent thrombus as bail-out in unsuccessful thrombectomy, unknown origin) of any location, grade or clinical presentation.

Patients undergoing an initial treatment or a retreatment of the index lesion.

Patients with or without acute demarcated ischemic infarction on pre-interventional imaging.

Balloon angioplasty prior to or after delivering the stent was optional.

All types of balloons for pre- or post-dilatation were allowed.

All types of access material (ie, guiding catheters, aspiration catheters, microcatheters and microguidewires).

All types of antiplatelet protocols before, during and after the procedure.

We defined the following exclusion criteria:

Acute intracranial hemorrhage.

Additional stenting of stenosis adjacent to treated aneurysm.

Treatment of cerebral vasospasms following aneurysmal subarachnoid hemorrhage.

The patients were categorized as elective cases if the stenosis was known and the treatment was planned and prepared several days or weeks before the treatment. These were all patients with recurrent neurological symptoms despite best medical treatment. Emergency cases were all patients with acute ischemic stroke with large vessel occlusion and a luminal narrowing discovered after mechanical thrombectomy.

Data collection

We documented demographic data for each patient, stenosis grade according to the WASID method, 6 location of the stenosis, and pre-, peri-, and post-interventional antiplatelet therapy. Additionally, we recorded peri-procedural, post-procedural, and delayed complications, as well as clinical and anatomical imaging outcomes.

The stenosis diameter in relation to the adjacent normal vessel diameter was assessed both before and after implantation of the pEGASUS-HPC stent, including any additional balloon dilatation if performed. Successful treatment was defined as a reduction of the initial stenosis by ≥50%.

A thorough evaluation of all procedures entailed documenting and analyzing all materials used, procedural complications and their management, as well as the type of anesthesia administered. Subjective impressions of the operators were also recorded, categorized as ‘pushing through the microcatheter’ (satisfactory/unsatisfactory) and ‘positioning of the stent’ (satisfactory/unsatisfactory).

Revascularization rates of the stenosis were assessed based on the percentage of residual stenosis and stenosis improvement at the conclusion of the procedure and during follow-up, if available. All available follow-up assessments, including digital subtraction angiography (DSA), magnetic resonance angiography (MRA) and CT angiography (CTA), were included. Early follow-ups were conducted based on individual clinical circumstances post-treatment.

Stent patency was graded using a 4-stage scale:

No stenosis.

≤50% stenosis.

>50% stenosis.

Occlusion, assessed at the conclusion of the procedure and during all available follow-ups.

Statistical analysis

All data were collected anonymously in an Excel spreadsheet. Image evaluations were conducted at our neurovascular center using our routine PACS (Picture Archiving and Communication System).

Demographic data, baseline and follow-up data as well as procedural characteristics were summarized and reported as mean±SD and range for continuous variables. Categorical data were summarized as numbers and percentages.

Basic demographics

From August 2021 to November 2023 we identified 41 patients in whom we treated 42 stenoses. Among them, 21 patients (51.2%) were female and the mean±SD age was 71±10.8 years.

Five patients underwent elective treatment, accounting for a total of six interventions (13.9%). The remaining 37 patients (86.1%) received treatment in the context of mechanical thrombectomy. During the same period we performed 826 thrombectomies resulting in intracranial bail-out stenting in emergency cases using the pEGASUS-HPC in 4.5% of all thrombectomies. This is in line with recent trends in endovascular therapies. 7 8

Before stent implantation the stenosis grade in relation to the normal adjacent vessel diameter averaged 87.8±9.9%. Following stent implantation, the residual stenosis measured 34.5±15.8% in emergency cases and 29.2±18.1% in elective cases ( table 1 ).

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Basic demographics, clinical and angiographic characteristics and outcome

The majority of stenoses were located in the anterior circulation (74.4%), with the posterior circulation accounting for the remaining 25.6%. Predominantly, stenoses were found in the middle cerebral artery (M1: 46.5%; M2: 9.3%), followed by the internal carotid artery (ICA, C2: 7.0%; C3 and C5 each 0%; C4 and C6 each 4.7%, C7: 16.3%, according to Bouthillier classification 9 ). Stenoses were also observed in the vertebral artery (14.0%) and basilar artery (9.3%). In six emergency cases (14.0%) dissection was diagnosed as the underlying cause, with an additional five patients (3 emergency, 2 elective) presenting with suspected dissection.

All patients underwent general anesthesia. Intra-arterial blood pressure measurements were performed primarily through femoral access sheaths during the intervention and via peripheral access (mostly radial artery) post-interventionally. The systolic arterial pressure threshold was set at 140 mmHg and efforts were made to avoid blood pressure spikes.

Endovascular treatment

For the treatment of 42 stenoses a total of 50 pEGASUS-HPC stents were used: 46 (92.0%) were implanted and four (8.0% of all stents) were discarded. To mitigate the risk of secondary dislocation and maximize the utilization of the stent’s radial force, pEGASUS-HPC stents were intentionally oversized, with a mean oversizing of 26.1±37.3% compared with the parent vessel diameter.

In three patients two stents were implanted during the same session: one instance involved a slight dislocation of the first stent necessitating the placement of an additional stent while, in another case, two stents were used to cover a long stenotic segment. Furthermore, one patient with bilateral high-grade V4 stenosis was successfully treated in two separate interventions.

In five cases (13.2%) a transition from a balloon-expandable stent to the pEGASUS-HPC stent occurred due to the inability to deliver the stent to the target lesion. Balloon angioplasty was performed in 41 interventions (95.3%), with the NeuroSpeed balloon (Acandis) being the most frequently used (55.8%). For stent deployment, the NeuroSpeed balloon catheter was employed in 51.2% of interventions followed by Excelsior SL10 (Stryker, Fremont, California, USA) in 34.9%. In all four cases where the pEGASUS-HPC stent was discarded, a NeuroSpeed balloon was used as the delivery microcatheter. This was due to dislocation caused by friction in three interventions, while insurmountable friction prevented the delivery of the stent in one patient. In these instances, the Excelsior SL10 microcatheter was used for the successful deployment of the second pEGASUS-HPC stent. In dilatation, we deliberately chose balloons that were undersized compared with the estimated vessel diameter in 97.5% of cases to mitigate the risk of high-grade dissection and vessel perforation.

For the first balloon the undersizing averaged 23.9±22.1%, with diameters ranging from 1.5 to 4.0 mm and lengths from 8 to 20 mm. If a second balloon was employed, the mean undersizing was 16.2±22.7%, using the same lengths. Pre-dilatation alone was used in 28 cases (58.1%), while pre- and post-dilatation were conducted in 13 cases (30.2%). Post-dilatation alone was performed in two cases (4.7%). In two cases (4.7%) angioplasty was not used as these were suspected dissection cases.

Figures 1 and 2 show examples of pre- and post-dilatation and pre-dilatation only, respectively. All angioplasty balloons used were uncoated and none were drug-eluting. Thrombectomy before stent implantation was carried out in 37 cases (86.1%), typically using the SAVE technique. 10 The mean number of thrombectomy maneuvers was 3.6±3.4, with a maximum of 16 thrombectomy maneuvers recorded in one intervention. The criteria for implementing bail-out stenting in cases of unsuccessful thrombectomy were the identification of high-grade stenosis in the previously occluded vessel, or the presence of a stenosis exhibiting low and/or turbulent flow, or a tendency toward early reocclusion. Regarding the infarct core, there was no specific quantitative threshold to avoid stenting. Systemic thrombolysis before intervention was administered in 12 patients, constituting 32.4% of patients with acute stroke, and the mean dose administered was 58.4±17.8 mg.

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Patient with acute ischemic stroke postoperatively (tumor nephrectomy). (A) Initial complete occlusion of left M1. Partial leptomeningeal collateralization from left anterior cerebral artery (ACA). (B) Proximal M1 stenosis after two thrombectomies using the SAVE technique. Possible wall-adherent plaque (note the fuzzy margin of the distal stenosis). (C) Pre-dilatation using a NeuroSpeed balloon catheter (2.0×8.0 mm) after 500 mg aspirin IV and 2500 IE heparin IV. (D) Minor residual stenosis following pEGASUS-HPC stent implantation (3.5×15 mm). (E) Post-dilatation using same NeuroSpeed balloon catheter (2.0×8.0 mm). (F) Final run (modified Treatment in Cerebral Ischemia grade 2c). ACA collaterals are diminished due to normal middle cerebral artery flow.

Patient with acute ischemic stroke. (A) Initial occlusion of distal right M1 despite Actilyse IV, aplasia of right A1. (B) High-grade M2 stenosis (superior trunk) after three thrombectomies using the SAVE technique. (C) Pre-dilatation using a Maverick balloon catheter (1.5×20 mm). (D) Positioning of pEGASUS-HPC stent (3.5×15 mm) from superior trunk of M2 to distal M1 following 500 mg aspirin IV. (E) Control run, no post-dilatation necessary. (F) Final run, complete revascularization (modified Treatment in Cerebral Ischemia grade 3).

Antiplatelet protocols

In all elective cases, patients received 100 mg aspirin orally and 75 mg clopidogrel orally before the procedure, along with 250 mg aspirin and 5000 IU heparin IV during the procedure. After the procedure, patients were prescribed 100 mg aspirin orally and 75 mg clopidogrel orally for 6–12 months. Antiplatelet function tests using the multiplate test (Roche Diagnostics, Mannheim, Germany) were conducted for all patients on the day before the procedure, with all patients having a satisfactory response to aspirin and clopidogrel.

In emergency interventions the antiplatelet protocol varied, largely due to pre-existing medications administered for other conditions. Details concerning the individual antiplatelet protocols used are summarized in table 2 .

Antiplatelet/anticoagulant protocols and thrombolytica

Technical outcome

In the final DSA run, all implanted pEGASUS-HPC stents were found to be patent. The mean±SD initial stenosis overall was 87.8±9.9% and, after stenting, the residual stenosis was 34.8±15.6% resulting in a mean stenosis improvement of 53.0±18.0%. In emergency interventions the stenosis improvement was 52.6±17.3%, while in elective interventions it was 58.1±21.7%.

At the first follow-up, which was available for 16 patients (37.2%) after a mean of 32.1 days, imaging modalities included 43.8% DSA, 31.2% CTA, and 25.0% MRA. Among these, no in-stent stenosis was observed in seven patients (43.7% of available follow-ups), moderate restenosis was found in three patients (18.7%), and severe stenosis in two patients (12.5%). Additionally, one stent was occluded (6.2%). In one case residual stenosis showed further improvement at the first follow-up and, in another case, a stent was impossible to evaluate by CTA due to beam hardening artifacts.

Clinical outcome

The modified Rankin Scale (mRS) was used to assess all patients at hospital discharge. Overall, the mRS score improved slightly from pre-intervention (mean 4.2) to post-intervention (mean 3.9), with a slightly more pronounced difference observed in emergency patients (pre-intervention mean 4.5, post-intervention mean 4.1). In elective patients, the mean mRS score of 2.7 showed no change. Improvement in the mRS score was recorded in 19 patients, with a good clinical outcome (mRS 0–2) achieved in nine patients overall (20.9%), including seven emergency interventions (19.9%).

Of the 37 emergency patients, 11 (25.6%) died with four developing sepsis, one experiencing massive abdominal bleeding and hemorrhagic shock, one suffering cardiogenic shock, and five encountering basilar thrombosis with vertebrobasilar infarction. No death was directly related to stent implantation. One death (due to hemorrhagic shock) was almost certainly caused by femoral access site bleeding after intra-/post-procedural tirofiban infusion.

Intra-procedural technical and clinical complications

Revascularization of the occluded vessel or improvement of stenosis was achieved in all cases with a reduction of the initial stenosis by ≥50%. No intra-procedural hemorrhagic complications or directly pEGASUS-related complications occurred in elective cases. However, in one patient (16.7%) dissection distal to the stenosis occurred after pre-dilatation. In response, a flow diverter (p64 MW-HPC 350-21, Phenox) was implanted and the remaining intervention proceeded without further incident.

In emergency interventions, seven cases (18.9%) experienced major intra-procedural complications. In two cases, emboli occurred distally to the stent. In the first case it was managed with microwire fragmentation and continued tirofiban infusion, achieving an overall mTICI 2c recanalization. Unfortunately, the patient’s neurological deficit did not improve post-intervention. Additionally, the patient suffered from severe urinary tract infection and died 4 days after the intervention due to combined severe acute ischemic infarction (National Institutes of Health Stroke Scale (NIHSS) score of 19 pre-intervention) and sepsis. In the second case an embolism distal to the stenosis occurred immediately after pre-dilatation and was treated with aspiration thrombectomy and tirofiban infusion, resulting in partial recanalization. However, the patient died the following day.

In a patient in their 80s with acute left-sided distal ICA occlusion, an acute in-stent thrombosis occurred in the M1 segment. Additionally, the patient suffered from a high-grade stenosis in the distal cervical segment of the ipsilateral ICA. Both conditions were addressed in the same intervention with a balloon-expandable stent (Multilink Vision 4×15, Boston Scientific) deployed to treat the high-grade stenosis. The in-stent thrombosis of the pEGASUS-HPC stent was managed with tirofiban and angioplasty, resulting in patency of the stent and a final mTICI 2c result. The patient’s condition slightly improved from a mRS score of 5 to 4 and a NIHSS score from 20 to 16.

Three (8.1%) iatrogenic dissections occurred, all in emergency cases. Two were caused by failed positioning of balloon-mounted stents and one was caused by pre-dilatation. These patients were successfully treated and experienced both angiographic and clinical improvement with mRS scores improving from 4 to 1, 4 to 3, and 5 to 4.

Additionally, one (2.7%) extracranial paravasation in nuchal tissue adjacent to the distal V3 segment of the vertebral artery occurred due to failed positioning of a balloon-expandable stent (PRO-Kinetic Energy 3×9, Biotronik SE & Co. KG, Berlin, Germany). The vessel was reconstructed with two flow diverters (2× p64 MW HPC 4.0×24 mm, Phenox).

Post-procedural complications

Post-procedural complications related to the pEGASUS-HPC stent system occurred in three (8.1%) patients undergoing an emergency intervention, consisting of one hemorrhagic and two ischemic events. In one emergency patient treated with two stents due to slight dislocation of the first stent, delayed post-procedural loading with clopidogrel resulted in subtotal occlusion of the stent within less than 24 hours despite successful initial revascularization. This led to aspiration thrombectomy and tirofiban bolus infusion, but the patient suffered partial MCA infarction and neurological deterioration. Another patient with M1 occlusion experienced post-procedural subarachnoid hemorrhage under continuous tirofiban infusion and died 6 days later due to additional complications. The third patient treated for an M1 occlusion due to an underlying high-grade stenosis developed high-grade in-stent stenosis, partial MCA infarction, three-valve endocarditis with sepsis, and non-occlusive mesenteric ischemia and died 3 days after the stent procedure.

In three (50.0%) of the elective interventions, post-procedural stent-related complications occurred. One patient treated for high-grade stenosis of the C7 segment of the left ICA with pEGASUS-HPC stentand with short-term postinterventional tirofiban perfusor experienced post-procedural symptomatic intracerebral hemorrhage (sICH) with motoric aphasia. Another patient with high-grade ICA stenosis underwent successful revascularization with the pEGASUS stent but required an additional flow diverter for the treatment of iatrogenic dissection distal to the stenosis. The third patient with bilateral high-grade distal V4 stenosis and elective stenting of the left-sided stenosis experienced rotating vertigo, nausea, and gait ataxia, possibly correlated with a small pontine infarction observed on MRI 7 days after stent implantation.

In this retrospective observational single-center study we present our experience with the pEGASUS-HPC stent system. Revascularization achieved success rates of 100%, defined as an improvement in the stenosis grade of 50% or more. Subsequent occlusion after initial treatment was observed in three of the 50 stents deployed. The majority of interventions consisted of futile thrombectomies (87.8%), with a minority comprising elective interventions for symptomatic stenosis (12.2%).

The findings of our study are noteworthy in light of the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial, which reported a higher incidence of stroke or death in the stenting+best medical treatment group (14.7%) compared with the best medical treatment group (5.8%). 11 Since 2009 there have been significant technological advancements in intracranial stent systems. For example, the Wingspan stent used in the SAMMPRIS trial is a relatively complex stent that requires larger delivery catheters than the pEGASUS-HPC (0.027 inches vs 0.0165 inches). This difference in catheter size reflects improvements in stent design and delivery systems, allowing for more minimally invasive procedures with smaller access vessels. Such advancements contribute to enhanced safety and efficacy profiles of newer generation stents like the pEGASUS-HPC. This stent system received CE (Conformité Européenne) mark clearance in the European Union in 2021 for the treatment of aneurysms and intracranial stenosis. It is coated with a glycan-based hydrophilic multilayer polymer coating (HPC) that is a mere 10 nm thick and covalently bound to the stent material, thus offering a less thrombogenic stent surface. 5 12–14 This surface alteration mimics the biological properties of the glycocalyx present on the endothelium, contributing to improved biocompatibility and reduced thrombogenicity of the stent. 12 The coating does not compromise the mechanical properties of the pEGASUS-HPC stent. In vivo studies have shown no inflammatory response or intima hyperplasia. 14 15 The coating has been shown to reduce thrombogeneity of the coated devices and promising results were reported of the use of flow diverters coated with HPC and mono antiplatelet therapy 16 .

One of the primary competitors to the pEGASUS-HPC stent in terms of construction similarities is the Neuroform Atlas Stent (Stryker, Portage, USA). Although the Atlas stent is not certified for the treatment of intracranial stenosis according to IFU, intracranial stenosis treatment with a good safety profile using the Atlas stent was recently published. 17 However, we chose the pEGASUS-HPC mainly because it is certified for stenosis treatment and also because it is available with antithrombotic coating. While there is no comprehensive quantitative comparison of the radial force of intracranial stents available in the published literature, it is estimated that the radial force of the pEGASUS-HPC stent lies above that of the Atlas stent but below that of the Wingspan stent.

Other reasons for stent selection may be anatomical reasons. Residual stenosis may be less pronounced with balloon-expandable stents, 18 but in elongated vessels it can be impossible to push them to the desired destination. In five (13.2%) patients a primarily selected balloon-expandable stent could not be placed at the site of stenosis. Recent studies have highlighted the benefits of modern stent and catheter materials. 19–21

NeuroSpeed double-lumen PTA balloons were used in 55.8% of cases, effectively eliminating the need for further probing or exchange maneuvers. This approach demonstrates the importance of selecting appropriate tools and techniques to optimize procedural outcomes when dealing with challenging stent designs. 22 However, in four cases (8.0%) the pEGASUS-HPC stent had to be discarded because of friction and dislocation of the NeuroSpeed catheter, a problem not encountered with single-lumen catheters. The reasons were not clear, since deployment of the stents worked well in most of the cases and might be due to anatomical reasons.

Our study included patients with considerable heterogeneity in baseline characteristics including medical comorbidities, premedication, blood pressure, body mass index, demographics, and history of smoking. All patients treated with the pEGASUS-HPC stent for intracranial arterial stenosis were included, which also comprised individuals with a high likelihood of poor outcomes. Many interventions were conducted in the setting of severe acute ischemic stroke, resulting in complex scenarios. Therefore, a certain degree of negative selection bias is likely, as evidenced by the mean number of thrombectomy procedures of 3.6±3.4. When excluding these patients from the analysis and focusing solely on those with a pre-stroke mRS score ranging from 0 to 2, it was observed that 50% experienced an improved mRS, a finding consistent with other recent studies demonstrating favorable outcomes in rescue stenting scenarios. 7 23–25

Moreover, 67.0% of all treated patients were transferred from smaller primary stroke centers or, in some cases, from peripheral hospitals lacking neurological care units. This situation often resulted in prolonged transfer times for these patients. 26 Additionally, higher NIHSS and mRS scores are strong predictors of poor functional outcome. 27 28

All elective interventions were conducted following a dual antiplatelet protocol. However, there was considerable heterogeneity in emergency stentings (see table 2 ), with 32.4% pretreated with recombinant tissue plasminogen activators. Intra-procedurally, aspirin was used in 62.2% of cases while tirofiban was used in 56.8% (with some overlap of the two medications). The rate of intracranial hemorrhage (5.4% in failed thrombectomy) was not higher than in current studies on bail-out stenting in failed thrombectomy 7 24 or in studies evaluating the risk of sICH for thrombectomy in patients on different antiplatelet or anticoagulation therapy. 29 sICH rates were also below the rates of the intervention group in SAMMPRIS. 11

Our study has limitations inherent to its retrospective observational design, including a relatively small sample size and a short follow-up period. Most post-procedural mRS values were assessed at the time of hospital discharge (with a mean±SD of 12.3±9.5 days) and the 90-day mRS scores could potentially be significantly lower.

This single-center case series demonstrates the safety and viability of the HPC-coated pEGASUS stent system, especially in emergency situations when thrombectomy fails. Further randomized controlled trials are needed to evaluate the suspected additional benefit of the biomimetic HPC coating in emergency and elective endovascular treatment of intracranial arterial stenosis and to appraise the best stent design for the diverse clinical scenarios.

Ethics statements

Patient consent for publication.

Not applicable.

Ethics approval

Ethics approval for the study was provided by the Ethics Committee of the Association of Medical Doctors of the state of Thuringia. Verbal confirmation of the Ethics Committee was given on March 6, 2024 (reference number: 22748/2024/6). Patient informed consent was waived due to completely anonymized data collection and analysis. This report adheres to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement guidelines.

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Contributors DP: guarantor, data collection, study design, data analysis, writing of the manuscript and revisions. JK: data collection, careful revision of the manuscript. ELe and ELo: careful revision of the manuscript, data collection. DF, AS, K-TH: careful revision of the manuscript. DL: data collection, study design, careful revision of the manuscript.

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests DP: Phenox – travel expenses. DF: Medtronic, Cerenovous, Microvention, Penumbra, Stryker, Balt USA, Seimens, Mentice, Neurogami, Rapid.AI, Rapid Medical, Q’apel Medical, Arsenal Medical, Phenox, Scientia, NVMed, Perfuze, Vesalio – consulting fees; Medtronic, Cerenovous, Microvention, Penumbra, Stryker, Balt USA, Q’apel Medical – speaker honoraria; Medtronic, Cerenovous, Microvention, Penumbra, Stryker, Balt USA, Seimens, Mentice, Neurogami, Rapid.AI, Rapid Medical, Q’apel Medical, Arsenal Medical, Phenox, Scientia, NVMed, Perfuze, Vesalio – travel expenses; Scientia, MENTICE, Neurogami, NVMed, Perfuze – leadership role; Scientia, Perfuze, NVMED, Mentice, Neurogami – stock options. JK: Phenox travel expenses, speaker honoraria; Phenox, Microvention – consulting fees (money paid to institution). MG: Phenox – speaker honoraria, consulting fees; Microvention – speaker honoraria, consulting fees; Balt – consulting fees; Simq GmbH – Scientific advisory board member. AS, EL, EL: none. KT-H: Bayer – speaking honoraria, advisory fees. DL: Phenox – travel expenses, speaker honoraria (money paid to institution).

Provenance and peer review Not commissioned; externally peer reviewed.

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