how to find sources for literature review

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Literature Review: The What, Why and How-to Guide: Strategies to Finding Sources

• Literature Reviews?
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Useful Tool to Develop your Topic

Watch this video about Concept Mapping to become a Research Pro!

• Mind Mapping (also known as Concept Mapping) A helpful handout to show step by step how to create a concept map to map out a topic.

The Research Process

Planning : Before searching for articles or books, brainstorm to develop keywords that best describe your research question.

Searching : While searching take note of what other keywords are used to describe your topic  and use them to do more searches

     ♠ Most articles include a keyword section

     ♠ Key concepts names may change through time so make sure to check for variations

Organizing : Start organizing your results by categories/key concepts or any organizing principle that make sense for you. This will help you later when you are ready to analyze your findings

Analyzing : While reading, start making notes of key concepts and commonalities and disagreement among the research articles you find.

♠ Create a spreadsheet document to record what articles you are finding useful and why.

♠ Create fields to write summaries of articles or quotes for future citing and paraphrasing .

Writing : Synthesize your findings. Use your own voice to explain to your readers what you learned about the literature your search; its weaknesses and strengths; what is missing or ignored

Repeat : at any given time of the process you can go back to a previous step as necessary

Advanced Searching

• Boolean Searching (AND, OR, NOT): Words that help you connect your terms in a logical way for the system understand you 
• Proximity Searching (N/# or W/#): It allows you to search for two or more words that occur within a specified number of words (or fewer) of each other in the databases.
• Limiters/Filters : These are options available on the advanced page to let you control what type of document you want to search (articles), dates, language, peer-review, etc...
• Question mark (?) or a pound sign (#) for wildcard: useful when you don't know how something is spelled out, e.g. if you are looking about articles about color, if you want to find articles with the spelling colour (British English), you can use colo?r to find either spelling.
• Asterisk (*) for truncation: useful for getting results with keywords with multiple endings, e.g. comput* for computer, computers, computing , etc.
• UC Library Search Explained! Check the Search tips to better used our library catalog and articles search system
• EBSCOhost Searching Tips An useful guide about how to best search EBSCOhost databases
• ProQuest Database Search Tips An useful guide about how to best search ProQuest databases
• Are you working on an emerging topic? You are not likely to find many sources, which is good because you are trying to prove that this is a topic that needs more research. But, it is not enough to say that you found few or no articles on your topic in your field. You need to look broadly to other disciplines (also known as triangulation ) to see if your research topic has been studied from other perspectives as a way to validate the uniqueness of your research question.
• Are you working on something that has been studied extensively? Then you are going to find many sources and you will want to limit how far you want to look back. Use limiters to eliminate research that may be dated and opt to search for resources published within the last 5-10 years.
• Want to keep track of your searches , send alerts to your email when new articles in your topic are available? Create an account in any of our databases!

Following the Citation Trail!

Many databases today have special featured that show you how many times an article was cited by and by who and offer you links to those articles.

See below some recommended resources:

Web of Science consists of 9 databases: 

• Arts & Humanities Citation Index
• Social Sciences Citation Index
• Science Citation Index Expanded
• Conference Proceedings Citation Index - Sciences
• Conference Proceedings Citation Index - Social Sciences and Humanities
• Book Citation Index - Science
• Book Citation Index - Social Sciences and Humanities
• Emerging Sources Citation Index
• Current Chemical Reactions
• Index Chemicus
• Users who do not have a UCSBnet ID and password can search Google Scholar without authentication . However, you will not be able to access full text from sites that require a subscription.
• The Google Scholar link in the database list is proxied to allow UCSB users to easily access subscription resources after discovery in Google Scholar.
• In Google Scholar, expand the menu and select “Settings”
• Choose “Library links”
• Search on “university of california, santa barbara”
• Check the box for "University of California, Santa Barbara - Get it at UC" and save your preferences
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• Next: Keeping up with Research! >>
• Last Updated: Mar 5, 2024 11:44 AM
• URL: https://guides.library.ucsb.edu/litreview

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• Knowledge Base
• Working with sources

How to Find Sources | Scholarly Articles, Books, Etc.

Published on June 13, 2022 by Eoghan Ryan . Revised on May 31, 2023.

It’s important to know how to find relevant sources when writing a  research paper , literature review , or systematic review .

The types of sources you need will depend on the stage you are at in the research process , but all sources that you use should be credible , up to date, and relevant to your research topic.

There are three main places to look for sources to use in your research:

Research databases

• Your institution’s library
• Other online resources

Table of contents

Library resources, other online sources, other interesting articles, frequently asked questions about finding sources.

You can search for scholarly sources online using databases and search engines like Google Scholar . These provide a range of search functions that can help you to find the most relevant sources.

If you are searching for a specific article or book, include the title or the author’s name. Alternatively, if you’re just looking for sources related to your research problem , you can search using keywords. In this case, it’s important to have a clear understanding of the scope of your project and of the most relevant keywords.

Databases can be general (interdisciplinary) or subject-specific.

• You can use subject-specific databases to ensure that the results are relevant to your field.
• When using a general database or search engine, you can still filter results by selecting specific subjects or disciplines.

Example: JSTOR discipline search filter

Check the table below to find a database that’s relevant to your research.

Google Scholar

To get started, you might also try Google Scholar , an academic search engine that can help you find relevant books and articles. Its “Cited by” function lets you see the number of times a source has been cited. This can tell you something about a source’s credibility and importance to the field.

Example: Google Scholar “Cited by” function

Boolean operators

Boolean operators can also help to narrow or expand your search.

Boolean operators are words and symbols like AND , OR , and NOT that you can use to include or exclude keywords to refine your results. For example, a search for “Nietzsche NOT nihilism” will provide results that include the word “Nietzsche” but exclude results that contain the word “nihilism.”

Many databases and search engines have an advanced search function that allows you to refine results in a similar way without typing the Boolean operators manually.

Example: Project Muse advanced search

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You can find helpful print sources in your institution’s library. These include:

• Journal articles
• Encyclopedias
• Newspapers and magazines

Make sure that the sources you consult are appropriate to your research.

You can find these sources using your institution’s library database. This will allow you to explore the library’s catalog and to search relevant keywords. You can refine your results using Boolean operators .

Once you have found a relevant print source in the library:

• Consider what books are beside it. This can be a great way to find related sources, especially when you’ve found a secondary or tertiary source instead of a primary source .
• Consult the index and bibliography to find the bibliographic information of other relevant sources.

You can consult popular online sources to learn more about your topic. These include:

• Crowdsourced encyclopedias like Wikipedia

You can find these sources using search engines. To refine your search, use Boolean operators in combination with relevant keywords.

However, exercise caution when using online sources. Consider what kinds of sources are appropriate for your research and make sure the sites are credible .

Look for sites with trusted domain extensions:

• URLs that end with .edu are educational resources.
• URLs that end with .gov are government-related resources.
• DOIs often indicate that an article is published in a peer-reviewed , scientific article.

Other sites can still be used, but you should evaluate them carefully and consider alternatives.

If you want to know more about ChatGPT, AI tools , citation , and plagiarism , make sure to check out some of our other articles with explanations and examples.

• ChatGPT vs human editor
• ChatGPT citations
• Is ChatGPT trustworthy?
• Using ChatGPT for your studies
• What is ChatGPT?
• Chicago style
• Paraphrasing

 Plagiarism

• Types of plagiarism
• Self-plagiarism
• Avoiding plagiarism
• Academic integrity
• Consequences of plagiarism
• Common knowledge

Scribbr Citation Checker New

The AI-powered Citation Checker helps you avoid common mistakes such as:

• Missing commas and periods
• Incorrect usage of “et al.”
• Ampersands (&) in narrative citations
• Missing reference entries

You can find sources online using databases and search engines like Google Scholar . Use Boolean operators or advanced search functions to narrow or expand your search.

For print sources, you can use your institution’s library database. This will allow you to explore the library’s catalog and to search relevant keywords.

It is important to find credible sources and use those that you can be sure are sufficiently scholarly .

• Consult your institute’s library to find out what books, journals, research databases, and other types of sources they provide access to.
• Look for books published by respected academic publishing houses and university presses, as these are typically considered trustworthy sources.
• Look for journals that use a peer review process. This means that experts in the field assess the quality and credibility of an article before it is published.

When searching for sources in databases, think of specific keywords that are relevant to your topic , and consider variations on them or synonyms that might be relevant.

Once you have a clear idea of your research parameters and key terms, choose a database that is relevant to your research (e.g., Medline, JSTOR, Project MUSE).

Find out if the database has a “subject search” option. This can help to refine your search. Use Boolean operators to combine your keywords, exclude specific search terms, and search exact phrases to find the most relevant sources.

There are many types of sources commonly used in research. These include:

You’ll likely use a variety of these sources throughout the research process , and the kinds of sources you use will depend on your research topic and goals.

Scholarly sources are written by experts in their field and are typically subjected to peer review . They are intended for a scholarly audience, include a full bibliography, and use scholarly or technical language. For these reasons, they are typically considered credible sources .

Popular sources like magazines and news articles are typically written by journalists. These types of sources usually don’t include a bibliography and are written for a popular, rather than academic, audience. They are not always reliable and may be written from a biased or uninformed perspective, but they can still be cited in some contexts.

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Ryan, E. (2023, May 31). How to Find Sources | Scholarly Articles, Books, Etc.. Scribbr. Retrieved September 18, 2024, from https://www.scribbr.com/working-with-sources/finding-sources/

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Literature Review - what is a Literature Review, why it is important and how it is done

The research process.

• Evaluating Literature Reviews and Sources
• Tips for Writing Literature Reviews
• Writing Literature Review: Useful Sites
• Citation Resources
• Other Academic Writings
• Useful Resources

Finding sources (scholarly articles, research books, dissertations) for your literature review is part of the research process, a process that is iterative--you go back and forth along the process as new information is gather and analyze until all necessary data is acquire and you are ready to write. The main steps in this research process are:

Searching : While searching take note of what other keywords are used to describe your topic  and use them to do more searches

– Most articles include a keyword section – Key concepts may change name through time so make sure to check for variations

Organising : Start organizing your results by categories/key concepts or any organizing principle that make sense for you. This will help you later when you are ready to analyze your findings

Analysing : While reading, start making notes of key concepts and commonalities and disagreement among the research articles you find.

– Create a spreadsheet document to record what articles you are finding useful and why. – Create fields to write summaries of articles or quotes for future citing and paraphrasing .

Writing : Synthesize your findings. Use your own voice to explain to your readers what you learn about the literature your search; its weaknesses and strengths; what is missing or ignore

Repeat : at any given time of the process you can go back to a previous step as necessary

There is no magic number regarding how many sources you are going to need for your literature review, it all depends on the topic and what type of the literature review you are doing:

► Are you working on an emerging topic? You are not likely to find many sources, which is good because you are trying to prove that this is a topic that needs more research. But, it is not enough to say that you found few or no articles on your topic in your field. You need to look broadly to other disciplines (also known as triangulation ) to see if your research topic has been studied from other perspectives as a way to validate the uniqueness of your research question.

► Are you working on  something that has been studied extensively? Then you are going to find many sources and you will want to limit how far you want to look back. Use limiters to eliminate research that may be dated and opt to search for resources published within the last 5-10 years.

• << Previous: Home
• Next: Evaluating Literature Reviews and Sources >>
• Last Updated: Jul 3, 2024 10:56 AM
• URL: https://lit.libguides.com/Literature-Review

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• > Journals
• > BJPsych Advances
• > Volume 24 Issue 2
• > How to carry out a literature search for a systematic...

Article contents

• LEARNING OBJECTIVES
• DECLARATION OF INTEREST

Defining the clinical question

Scoping search, search strategy, sources to search, developing a search strategy, searching electronic databases, supplementary search techniques, obtaining unpublished literature, conclusions, how to carry out a literature search for a systematic review: a practical guide.

Published online by Cambridge University Press:  01 March 2018

Performing an effective literature search to obtain the best available evidence is the basis of any evidence-based discipline, in particular evidence-based medicine. However, with a vast and growing volume of published research available, searching the literature can be challenging. Even when journals are indexed in electronic databases, it can be difficult to identify all relevant studies without an effective search strategy. It is also important to search unpublished literature to reduce publication bias, which occurs from a tendency for authors and journals to preferentially publish statistically significant studies. This article is intended for clinicians and researchers who are approaching the field of evidence synthesis and would like to perform a literature search. It aims to provide advice on how to develop the search protocol and the strategy to identify the most relevant evidence for a given research or clinical question. It will also focus on how to search not only the published but also the unpublished literature using a number of online resources.

• Understand the purpose of conducting a literature search and its integral part of the literature review process

• Become aware of the range of sources that are available, including electronic databases of published data and trial registries to identify unpublished data

• Understand how to develop a search strategy and apply appropriate search terms to interrogate electronic databases or trial registries

A literature search is distinguished from, but integral to, a literature review. Literature reviews are conducted for the purpose of (a) locating information on a topic or identifying gaps in the literature for areas of future study, (b) synthesising conclusions in an area of ambiguity and (c) helping clinicians and researchers inform decision-making and practice guidelines. Literature reviews can be narrative or systematic, with narrative reviews aiming to provide a descriptive overview of selected literature, without undertaking a systematic literature search. By contrast, systematic reviews use explicit and replicable methods in order to retrieve all available literature pertaining to a specific topic to answer a defined question (Higgins Reference Higgins and Green 2011 ). Systematic reviews therefore require a priori strategies to search the literature, with predefined criteria for included and excluded studies that should be reported in full detail in a review protocol.

Performing an effective literature search to obtain the best available evidence is the basis of any evidence-based discipline, in particular evidence-based medicine (Sackett Reference Sackett 1997 ; McKeever Reference McKeever, Nguyen and Peterson 2015 ). However, with a vast and growing volume of published research available, searching the literature can be challenging. Even when journals are indexed in electronic databases, it can be difficult to identify all relevant studies without an effective search strategy (Hopewell Reference Hopewell, Clarke and Lefebvre 2007 ). In addition, unpublished data and ‘grey’ literature (informally published material such as conference abstracts) are now becoming more accessible to the public. It is important to search unpublished literature to reduce publication bias, which occurs because of a tendency for authors and journals to preferentially publish statistically significant studies (Dickersin Reference Dickersin and Min 1993 ). Efforts to locate unpublished and grey literature during the search process can help to reduce bias in the results of systematic reviews (Song Reference Song, Parekh and Hooper 2010 ). A paradigmatic example demonstrating the importance of capturing unpublished data is that of Turner et al ( Reference Turner, Matthews and Linardatos 2008 ), who showed that using only published data in their meta-analysis led to effect sizes for antidepressants that were one-third (32%) larger than effect sizes derived from combining both published and unpublished data. Such differences in findings from published and unpublished data can have real-life implications in clinical decision-making and treatment recommendation. In another relevant publication, Whittington et al ( Reference Whittington, Kendall and Fonagy 2004 ) compared the risks and benefits of selective serotonin reuptake inhibitors (SSRIs) in the treatment of depression in children. They found that published data suggested favourable risk–benefit profiles for SSRIs in this population, but the addition of unpublished data indicated that risk outweighed treatment benefits. The relative weight of drug efficacy to side-effects can be skewed if there has been a failure to search for, or include, unpublished data.

In this guide for clinicians and researchers on how to perform a literature search we use a working example about efficacy of an intervention for bipolar disorder to demonstrate the search techniques outlined. However, the overarching methods described are purposefully broad to make them accessible to all clinicians and researchers, regardless of their research or clinical question.

The review question will guide not only the search strategy, but also the conclusions that can be drawn from the review, as these will depend on which studies or other forms of evidence are included and excluded from the literature review. A narrow question will produce a narrow and precise search, perhaps resulting in too few studies on which to base a review, or be so focused that the results are not useful in wider clinical settings. Using an overly narrow search also increases the chances of missing important studies. A broad question may produce an imprecise search, with many false-positive search results. These search results may be too heterogeneous to evaluate in one review. Therefore from the outset, choices should be made about the remit of the review, which will in turn affect the search.

A number of frameworks can be used to break the review question into concepts. One such is the PICO (population, intervention, comparator and outcome) framework, developed to answer clinical questions such as the effectiveness of a clinical intervention (Richardson Reference Richardson, Wilson and Nishikawa 1995 ). It is noteworthy that ‘outcome’ concepts of the PICO framework are less often used in a search strategy as they are less well defined in the titles and abstracts of available literature (Higgins Reference Higgins and Green 2011 ). Although PICO is widely used, it is not a suitable framework for identifying key elements of all questions in the medical field, and minor adaptations are necessary to enable the structuring of different questions. Other frameworks exist that may be more appropriate for questions about health policy and management, such as ECLIPSE (expectation, client group, location, impact, professionals, service) (Wildridge Reference Wildridge and Bell 2002 ) or SPICE (setting, perspective, intervention, comparison, evaluation) for service evaluation (Booth Reference Booth 2006 ). A detailed overview of frameworks is provided in Davies ( Reference Davies 2011 ).

Before conducting a comprehensive literature search, a scoping search of the literature using just one or two databases (such as PubMed or MEDLINE) can provide valuable information as to how much literature for a given review question already exists. A scoping search may reveal whether systematic reviews have already been undertaken for a review question. Caution should be taken, however, as systematic reviews that may appear to ask the same question may have differing inclusion and exclusion criteria for studies included in the review. In addition, not all systematic reviews are of the same quality. If the original search strategy is of poor quality methodologically, original data are likely to have been missed and the search should not simply be updated (compare, for example, Naughton et al ( Reference Naughton, Clarke and O'Leary 2014 ) and Caddy et al ( Reference Caddy, Amit and McCloud 2015 ) on ketamine for treatment-resistant depression).

The first step in conducting a literature search should be to develop a search strategy. The search strategy should define how relevant literature will be identified. It should identify sources to be searched (list of databases and trial registries) and keywords used in the literature (list of keywords). The search strategy should be documented as an integral part of the systematic review protocol. Just as the rest of a well-conducted systematic review, the search strategy used needs to be explicit and detailed such that it could reproduced using the same methodology, with exactly the same results, or updated at a later time. This not only improves the reliability and accuracy of the review, but also means that if the review is replicated, the difference in reviewers should have little effect, as they will use an identical search strategy. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement was developed to standardise the reporting of systematic reviews (Moher Reference Moher, Liberati and Tetzlaff 2009 ). The PRISMA statement consists of a 27-item checklist to assess the quality of each element of a systematic review (items 6, 7 and 8 relate to the quality of literature searching) and also to guide authors when reporting their findings.

There are a number of databases that can be searched for literature, but the identification of relevant sources is dependent on the clinical or research question (different databases have different focuses, from more biology to more social science oriented) and the type of evidence that is sought (i.e. some databases report only randomised controlled trials).

• MEDLINE and Embase are the two main biomedical literature databases. MEDLINE contains more than 22 million references from more than 5600 journals worldwide. In addition, the MEDLINE In-Process & Other Non-Indexed Citations database holds references before they are published on MEDLINE. Embase has a strong coverage of drug and pharmaceutical research and provides over 30 million references from more than 8500 currently published journals, 2900 of which are not in MEDLINE. These two databases, however, are only available to either individual subscribers or through institutional access such as universities and hospitals. PubMed, developed by the National Center for Biotechnology Information of the US National Library of Medicine, provides access to a free version of MEDLINE and is accessible to researchers, clinicians and the public. PubMed comprises medical and biomedical literature indexed in MEDLINE, but provides additional access to life science journals and e-books.

In addition, there are a number of subject- and discipline-specific databases.

• PsycINFO covers a range of psychological, behavioural, social and health sciences research.

• The Cochrane Central Register of Controlled Trials (CENTRAL) hosts the most comprehensive source of randomised and quasi-randomised controlled trials. Although some of the evidence on this register is also included in Embase and MEDLINE, there are over 150 000 reports indexed from other sources, such as conference proceedings and trial registers, that would otherwise be less accessible (Dickersin Reference Dickersin, Manheimer and Wieland 2002 ).

• The Cumulative Index to Nursing and Allied Health Literature (CINAHL), British Nursing Index (BNI) and the British Nursing Database (formerly BNI with Full Text) are databases relevant to nursing, but they span literature across medical, allied health, community and health management journals.

• The Allied and Complementary Medicine Database (AMED) is a database specifically for alternative treatments in medicine.

The examples of specific databases given here are by no means exhaustive, but they are popular and likely to be used for literature searching in medicine, psychiatry and psychology. Website links for these databases are given in Box 1 , along with links to resources not mentioned above. Box 1 also provides a website link to a couple of video tutorials for searching electronic databases. Box 2 shows an example of the search sources chosen for a review of a pharmacological intervention of calcium channel antagonists in bipolar disorder, taken from a recent systematic review (Cipriani Reference Cipriani, Saunders and Attenburrow 2016a ).

BOX 1 Website links of search sources to obtain published and unpublished literature

Electronic databases

• MEDLINE/PubMed: www.ncbi.nlm.nih.gov/pubmed

• Embase: www.embase.com

• PsycINFO: www.apa.org/psycinfo

• Cochrane Central Register of Controlled Trials (CENTRAL): www.cochranelibrary.com

• Cumulative Index of Nursing and Allied Health Literature (CINAHL): www.cinahl.com

• British Nursing Index: www.bniplus.co.uk

• Allied and Complementary Medicine Database: https://www.ebsco.com/products/research-databases/amed-the-allied-and-complementary-medicine-database

Grey literature databases

• BIOSIS Previews (part of Thomson Reuters Web of Science): https://apps.webofknowledge.com

Trial registries

• ClinicalTrials.gov: www.clinicaltrials.gov

• Drugs@FDA: www.accessdata.fda.gov/scripts/cder/daf

• European Medicines Agency (EMA): www.ema.europa.eu

• World Health Organization International Clinical Trials Registry Platform (WHO ICTRP): www.who.int/ictrp

• GlaxoSmithKline Study Register: www.gsk-clinicalstudyregister.com

• Eli-Lilly clinical trial results: https://www.lilly.com/clinical-study-report-csr-synopses

Guides to further resources

• King's College London Library Services: http://libguides.kcl.ac.uk/ld.php?content_id=17678464

• Georgetown University Medical Center Dahlgren Memorial Library: https://dml.georgetown.edu/core

• University of Minnesota Biomedical Library: https://hsl.lib.umn.edu/biomed/help/nursing

Tutorial videos

• Searches in electronic databases: http://library.buffalo.edu/hsl/services/instruction/tutorials.html

• Using the Yale MeSH Analyzer tool: http://library.medicine.yale.edu/tutorials/1559

BOX 2 Example of search sources chosen for a review of calcium channel antagonists in bipolar disorder (Cipriani Reference Cipriani, Saunders and Attenburrow 2016a )

Electronic databases searched:

• MEDLINE In-Process and Other Non-Indexed Citations

For a comprehensive search of the literature it has been suggested that two or more electronic databases should be used (Suarez-Almazor Reference Suarez-Almazor, Belseck and Homik 2000 ). Suarez-Almazor and colleagues demonstrated that, in a search for controlled clinical trials (CCTs) for rheumatoid arthritis, osteoporosis and lower back pain, only 67% of available citations were found by both Embase and MEDLINE. Searching MEDLINE alone would have resulted in 25% of available CCTs being missed and searching Embase alone would have resulted in 15% of CCTs being missed. However, a balance between the sensitivity of a search (an attempt to retrieve all relevant literature in an extensive search) and the specificity of a search (an attempt to retrieve a more manageable number of relevant citations) is optimal. In addition, supplementing electronic database searches with unpublished literature searches (see ‘Obtaining unpublished literature’ below) is likely to reduce publication bias. The capacity of the individuals or review team is likely largely to determine the number of sources searched. In all cases, a clear rationale should be outlined in the review protocol for the sources chosen (the expertise of an information scientist is valuable in this process).

Important methodological considerations (such as study design) may also be included in the search strategy. Dependent on the databases and supplementary sources chosen, filters can be used to search the literature by study design (see ‘Searching electronic databases’). For instance, if the search strategy is confined to one study design term only (e.g. randomised controlled trial, RCT), only the articles labelled in this way will be selected. However, it is possible that in the database some RCTs are not labelled as such, so they will not be picked up by the filtered search. Filters can help reduce the number of references retrieved by the search, but using just one term is not 100% sensitive, especially if only one database is used (i.e. MEDLINE). It is important for systematic reviewers to know how reliable such a strategy can be and treat the results with caution.

Identifying search terms

Standardised search terms are thesaurus and indexing terms that are used by electronic databases as a convenient way to categorise articles, allowing for efficient searching. Individual database records may be assigned several different standardised search terms that describe the same or similar concepts (e.g. bipolar disorder, bipolar depression, manic–depressive psychosis, mania). This has the advantage that even if the original article did not use the standardised term, when the article is catalogued in a database it is allocated that term (Guaiana Reference Guaiana, Barbui and Cipriani 2010 ). For example, an older paper might refer to ‘manic depression’, but would be categorised under the term ‘bipolar disorder’ when catalogued in MEDLINE. These standardised search terms are called MeSH (medical subject headings) in MEDLINE and PubMed, and Emtree in Embase, and are organised in a hierarchal structure ( Fig. 1 ). In both MEDLINE and Embase an ‘explode’ command enables the database to search for a requested term, as well as specific related terms. Both narrow and broader search terms can be viewed and selected to be included in the search if appropriate to a topic. The Yale MeSH Analyzer tool ( mesh.med.yale.edu ) can be used to help identify potential terms and phrases to include in a search. It is also useful to understand why relevant articles may be missing from an initial search, as it produces a comparison grid of MeSH terms used to index each article (see Box 1 for a tutorial video link).

FIG 1 Search terms and hierarchical structure of MeSH (medical subject heading) in MEDLINE and PubMed.

In addition, MEDLINE also distinguishes between MeSH headings (MH) and publication type (PT) terms. Publication terms are less about the content of an article than about its type, specifying for example a review article, meta-analysis or RCT.

Both MeSH and Emtree have their own peculiarities, with variations in thesaurus and indexing terms. In addition, not all concepts are assigned standardised search terms, and not all databases use this method of indexing the literature. It is advisable to check the guidelines of selected databases before undertaking a search. In the absence of a MeSH heading for a particular term, free-text terms could be used.

Free-text terms are used in natural language and are not part of a database’s controlled vocabulary. Free-text terms can be used in addition to standardised search terms in order to identify as many relevant records as possible (Higgins Reference Higgins and Green 2011 ). Using free-text terms allows the reviewer to search using variations in language or spelling (e.g. hypomani* or mania* or manic* – see truncation and wildcard functions below and Fig. 2 ). A disadvantage of free-text terms is that they are only searched for in the title and abstracts of database records, and not in the full texts, meaning that when a free-text word is used only in the body of an article, it will not be retrieved in the search. Additionally, a number of specific considerations should be taken into account when selecting and using free-text terms:

• synonyms, related terms and alternative phrases (e.g. mood instability, affective instability, mood lability or emotion dysregulation)

• abbreviations or acronyms in medical and scientific research (e.g. magnetic resonance imaging or MRI)

• lay and medical terminology (e.g. high blood pressure or hypertension)

• brand and generic drug names (e.g. Prozac or fluoxetine)

• variants in spelling (e.g. UK English and American English: behaviour or behavior; paediatric or pediatric).

FIG 2 Example of a search strategy about bipolar disorder using MEDLINE (Cipriani Reference Cipriani, Saunders and Attenburrow 2016a ). The strategy follows the PICO framework and includes MeSH terms, free-text keywords and a number of other techniques, such as truncation, that have been outlined in this article. Numbers in bold give the number of citations retrieved by each search.

Truncation and wildcard functions can be used in most databases to capture variations in language:

• truncation allows the stem of a word that may have variant endings to be searched: for example, a search for depress* uses truncation to retrieve articles that mention both depression and depressive; truncation symbols may vary by database, but common symbols include: *, ! and #

• wild cards substitute one letter within a word to retrieve alternative spellings: for example, ‘wom?n’ would retrieve the terms ‘woman’ and ‘women’.

Combining search terms

Search terms should be combined in the search strategy using Boolean operators. Boolean operators allow standardised search terms and free-text terms to be combined. There are three main Boolean operators – AND, OR and NOT ( Fig. 3 ).

• OR – this operator is used to broaden a search, finding articles that contain at least one of the search terms within a concept. Sets of terms can be created for each concept, for example the population of interest: (bipolar disorder OR bipolar depression). Parentheses are used to build up search terms, with words within parentheses treated as a unit.

• AND – this can be used to join sets of concepts together, narrowing the retrieved literature to articles that contain all concepts, for example the population or condition of interest and the intervention to be evaluated: (bipolar disorder OR bipolar depression) AND calcium channel blockers. However, if at least one term from each set of concepts is not identified from the title or abstract of an article, this article will not be identified by the search strategy. It is worth mentioning here that some databases can run the search also across the full texts. For example, ScienceDirect and most publishing houses allow this kind of search, which is much more comprehensive than abstract or title searches only.

• NOT – this operator, used less often, can focus a search strategy so that it does not retrieve specific literature, for example human studies NOT animal studies. However, in certain cases the NOT operator can be too restrictive, for example if excluding male gender from a population, using ‘NOT male’ would also mean that any articles about both males and females are not obtained by the search.

FIG 3 Example of Boolean operator concepts (the resulting search is the light red shaded area).

The conventions of each database should be checked before undertaking a literature search, as functions and operators may differ slightly between them (Cipriani Reference Cipriani, Saunders and Attenburrow 2016b ). This is particularly relevant when using limits and filters. Figure 2 shows an example search strategy incorporating many of the concepts described above. The search strategy is taken from Cipriani et al ( Reference Cipriani, Zhou and Del Giovane 2016a ), but simplified to include only one intervention.

Search filters

A number of filters exist to focus a search, including language, date and study design or study focus filters. Language filters can restrict retrieval of articles to the English language, although if language is not an inclusion criterion it should not be restricted, to avoid language bias. Date filters can be used to restrict the search to literature from a specified period, for example if an intervention was only made available after a certain date. In addition, if good systematic reviews exist that are likely to capture all relevant literature (as advised by an information specialist), date restrictions can be used to search additional literature published after the date of that included in the systematic review. In the same way, date filters can be used to update a literature search since the last time it was conducted. Reviewing the literature should be a timely process (new and potentially relevant evidence is produced constantly) and updating the search is an important step, especially if collecting evidence to inform clinical decision-making, as publications in the field of medicine are increasing at an impressive rate (Barber Reference Barber, Corsi and Furukawa 2016 ). The filters chosen will depend on the research question and nature of evidence that is sought through the literature search and the guidelines of the individual database that is used.

• Google Scholar

Google Scholar allows basic Boolean operators to be used in strings of search terms. However, the search engine does not use standardised search terms that have been tagged as in traditional databases and therefore variations of keywords should always be searched. There are advantages and disadvantages to using a web search engine such as Google Scholar. Google Scholar searches the full text of an article for keywords and also searches a wider range of sources, such as conference proceedings and books, that are not found in traditional databases, making it a good resource to search for grey literature (Haddaway Reference Haddaway, Collins and Coughlin 2015 ). In addition, Google Scholar finds articles cited by other relevant articles produced in the search. However, variable retrieval of content (due to regular updating of Google algorithms and the individual's search history and location) means that search results are not necessarily reproducible and are therefore not in keeping with replicable search methods required by systematic reviews. Google Scholar alone has not been shown to retrieve more literature than other traditional databases discussed in this article and therefore should be used in addition to other sources (Bramer Reference Bramer, Giustini and Kramer 2016 ).

Citation searching

Once the search strategy has identified relevant literature, the reference lists in these sources can be searched. This is called citation searching or backward searching, and it can be used to see where particular research topics led others. This method is particularly useful if the search identifies systematic reviews or meta-analyses of a similar topic.

Conference abstracts

Conference abstracts are considered ‘grey literature’, i.e. literature that is not formally published in journals or books (Alberani Reference Alberani, De Castro Pietrangeli and Mazza 1990 ). Scherer and colleagues found that only 52.6% of all conference abstracts go on to full publication of results, and factors associated with publication were studies that had RCT designs and the reporting of positive or significant results (Scherer Reference Scherer, Langenberg and von Elm 2007 ). Therefore, failure to search relevant grey literature might miss certain data and bias the results of a review. Although conference abstracts are not indexed in most major electronic databases, they are available in databases such as BIOSIS Previews ( Box 1 ). However, as with many unpublished studies, these data did not undergo the peer review process that is often a tool for assessing and possibly improving the quality of the publication.

Searching trial registers and pharmaceutical websites

For reviews of trial interventions, a number of trial registers exist. ClinicalTrials.gov ( clinicaltrials.gov ) provides access to information on public and privately conducted clinical trials in humans. Results for both published and unpublished studies can be found for many trials on the register, in addition to information about studies that are ongoing. Searching each trial register requires a slightly different search strategy, but many of the basic principles described above still apply. Basic searches on ClinicialTrials.gov include searching by condition, specific drugs or interventions and these can be linked using Boolean operators: for example, (bipolar disorder OR manic depressive disorder) AND lithium. As mentioned above, parentheses can be used to build up search terms. More advanced searches allow one to specify further search fields such as the status of studies, study type and age of participants. The US Food and Drug Administration (FDA) hosts a database providing information about FDA-approved drugs, therapeutic products and devices ( www.fda.gov ). The database (with open access to anyone, not only in the USA) can be searched by the drug name, its active ingredient or its approval application number and, for most drugs approved in the past 20 years or so, a review of clinical trial results (some of which remain unpublished) used as evidence in the approval process is available. The European Medicines Agency (EMA) hosts a similar register for medicines developed for use in the European Union ( www.ema.europa.eu ). An internet search will show that many other national and international trial registers exist that, depending on the review question, may be relevant search sources. The World Health Organization International Clinical Trials Registry Platform (WHO ICTRP; www.who.int/ictrp ) provides access to a central database bringing a number of these national and international trial registers together. It can be searched in much the same way as ClinicalTrials.gov.

A number of pharmaceutical companies now share data from company-sponsored clinical trials. GlaxoSmithKline (GSK) is transparent in the sharing of its data from clinical studies and hosts its own clinical study register ( www.gsk-clinicalstudyregister.com ). Eli-Lilly provides clinical trial results both on its website ( www.lillytrialguide.com ) and in external registries. However, other pharmaceutical companies, such as Wyeth and Roche, divert users to clinical trial results in external registries. These registries include both published and previously unpublished studies. Searching techniques differ for each company and hand-searching through documents is often required to identify studies.

Communication with authors

Direct communication with authors of published papers could produce both additional data omitted from published studies and other unpublished studies. Contact details are usually available for the corresponding author of each paper. Although high-quality reviews do make efforts to obtain and include unpublished data, this does have potential disadvantages: the data may be incomplete and are likely not to have been peer-reviewed. It is also important to note that, although reviewers should make every effort to find unpublished data in an effort to minimise publication bias, there is still likely to remain a degree of this bias in the studies selected for a systematic review.

Developing a literature search strategy is a key part of the systematic review process, and the conclusions reached in a systematic review will depend on the quality of the evidence retrieved by the literature search. Sources should therefore be selected to minimise the possibility of bias, and supplementary search techniques should be used in addition to electronic database searching to ensure that an extensive review of the literature has been carried out. It is worth reminding that developing a search strategy should be an iterative and flexible process (Higgins Reference Higgins and Green 2011 ), and only by conducting a search oneself will one learn about the vast literature available and how best to capture it.

Acknowledgements

We thank Sarah Stockton for her help in drafting this article. Andrea Cipriani is supported by the NIHR Oxford cognitive health Clinical Research Facility.

Select the single best option for each question stem

a an explicit and replicable method used to retrieve all available literature pertaining to a specific topic to answer a defined question

b a descriptive overview of selected literature

c an initial impression of a topic which is understood more fully as a research study is conducted

d a method of gathering opinions of all clinicians or researchers in a given field

e a step-by-step process of identifying the earliest published literature through to the latest published literature.

a does not need to be specified in advance of a literature search

b does not need to be reported in a systematic literature review

c defines which sources of literature are to be searched, but not how a search is to be carried out

d defines how relevant literature will be identified and provides a basis for the search strategy

e provides a timeline for searching each electronic database or unpublished literature source.

a the Cochrane Central Register of Controlled Trials (CENTRAL)

d the Cumulative Index to Nursing and Allied Health Literature (CINAHL)

e the British Nursing Index.

a bipolar disorder OR treatment

b bipolar* OR treatment

c bipolar disorder AND treatment

d bipolar disorder NOT treatment

e (bipolar disorder) OR (treatment).

a publication bias

b funding bias

c language bias

d outcome reporting bias

e selection bias.

MCQ answers

1 a 2 d 3 b 4 c 5 a

FIG 2 Example of a search strategy about bipolar disorder using MEDLINE (Cipriani 2016a). The strategy follows the PICO framework and includes MeSH terms, free-text keywords and a number of other techniques, such as truncation, that have been outlined in this article. Numbers in bold give the number of citations retrieved by each search.

This article has been cited by the following publications. This list is generated based on data provided by Crossref .

View all Google Scholar citations for this article.

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• Volume 24, Issue 2
• Lauren Z. Atkinson and Andrea Cipriani
• DOI: https://doi.org/10.1192/bja.2017.3

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• UOW Library
• Key guides for students

Literature Review

How to search effectively.

• Find examples of literature reviews
• How to write a literature review
• Grey literature

The  Literature searching interactive tutorial  includes self-paced, guided activities to assist you in developing  effective search skills..

1. Identify search words

Analyse your research topic or question.

• What are the main ideas?
• What concepts or theories have you already covered?
• Write down your main ideas, synonyms, related words and phrases.
• If you're looking for specific types of research, use these suggested terms: qualitative, quantitative, methodology, review, survey, test, trend (and more).
• Be aware of UK and US spelling variations. E.g. organisation OR organization, ageing OR aging.
• Interactive Keyword Builder
• Identifying effective keywords

2. Connect your search words

Find results with one or more search words.

Use OR between words that mean the same thing.

E.g.  adolescent  OR  teenager

This search will find results with either (or both) of the search words.

Find results with two search words

Use AND between words which represent the main ideas in the question.

E.g. adolescent AND “physical activity”

This will find results with both of the search words.

Exclude search words

Use NOT to exclude words that you don’t want in your search results.

E.g. (adolescent OR teenager) NOT “young adult”

3. Use search tricks

Search for different word endings.

Truncation *

The asterisk symbol * will help you search for different word endings.

E.g. teen* will find results with the words: teen, teens, teenager, teenagers

Specific truncation symbols will vary. Check the 'Help' section of the database you are searching.

Search for common phrases

Phrase searching “...........”

Double quotation marks help you search for common phrases and make your results more relevant.

E.g. “physical activity” will find results with the words physical activity together as a phrase.

Search for spelling variations within related terms

Wildcards ?

Wildcard symbols allow you to search for spelling variations within the same or related terms.

E.g. wom?n will find results with women OR woman

Specific wild card symbols will vary. Check the 'Help' section of the database you are searching.

Search terms within specific ranges of each other

Proximity  w/#

Proximity searching allows you to specify where your search terms will appear in relation to each other.

E.g.  pain w/10 morphine will search for pain within ten words of morphine

Specific proximity symbols will vary. Check the 'Help' section of the database you are searching.

4. Improve your search results

All library databases are different and you can't always search and refine in the same way. Try to be consistent when transferring your search in the library databases you have chosen.

Narrow and refine your search results by:

• year of publication or date range (for recent or historical research)
• document or source type (e.g. article, review or book)
• subject or keyword (for relevance). Try repeating your search using the 'subject' headings or 'keywords' field to focus your search
• searching in particular fields, i.e. citation and abstract. Explore the available dropdown menus to change the fields to be searched.

When searching, remember to:

Adapt your search and keep trying.

Searching for information is a process and you won't always get it right the first time. Improve your results by changing your search and trying again until you're happy with what you have found.

Keep track of your searches

Keeping track of searches saves time as you can rerun them, store references, and set up regular alerts for new research relevant to your topic.

Most library databases allow you to register with a personal account. Look for a 'log in', 'sign in' or 'register' button to get started.

• Literature review search tracker (Excel spreadsheet)

Manage your references

There are free and subscription reference management programs available on the web or to download on your computer.

• EndNote - The University has a license for EndNote. It is available for all students and staff, although is recommended for postgraduates and academic staff.
• Zotero - Free software recommended for undergraduate students.
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• Subject guides
• Researching for your literature review
• Literature sources

Researching for your literature review: Literature sources

• Literature reviews
• Before you start
• Develop a search strategy
• Keyword search activity
• Subject search activity
• Combined keyword and subject searching
• Online tutorials
• Apply search limits
• Run a search in different databases
• Supplementary searching
• Save your searches
• Manage results

Scholarly databases

It's important to make a considered decision as to where to search for your review of the literature. It's uncommon for a disciplinary area to be covered by a single publisher, so searching a single publisher platform or database is unlikely to give you sufficient coverage of studies for a review. A good quality review involves searching a number of databases individually.

The most common method is to search a combination of large inter-disciplinary databases such as Scopus & Web of Science Core Collection, and some subject-specific databases (such as PsycInfo or EconLit etc.). The Library databases are an excellent place to start for sources of peer-reviewed journal articles.

Depending on disciplinary expectations, or the topic of your review, you may also need to consider sources or search methods other than database searching. There is general information below on searching grey literature. However, due to the wide varieties of grey literature available, you may need to spend some time investigating sources relevant for your specific need.

Grey literature

Grey literature is information which has been produced outside of traditional publishing channels (where the main purpose of the producing body is not commercial publishing). One example may be Government publications.

Grey literature may be included in a literature review to minimise publication bias . The quality of grey literature can vary greatly - some may be reviewed whereas some may not have been through a traditional editorial process.

See the Grey Literature guide for further information on finding and evaluating grey sources.

In certain disciplines (such as physics) there can be a culture of preprints being made available prior to submissions to journals. There has also been a noticeable rise in preprints in medical and health areas in the wake of Covid-19.

If preprints are relevant for you, you can search preprint servers directly. Another option is to utilise a search engine such as Google Scholar to search specifically for preprints, as Google Scholar has timely coverage of most preprint servers including ArXiv , RePec , SSRN , BioRxiv , and MedRxiv . Articles in Press are not preprints, but are accepted manuscripts that are not yet formally published. Articles in Press have been made available as an early access online version of a paper that may not yet have received its final formatting or an allocation of a volume/issue number. As well as being available on a journal's website, Articles in Press are available in databases such as Scopus and Web of Science, and so (unlike preprints) don't necessarily require a separate search.

Conference papers

Conference papers are typically published in conference proceedings (the collection of papers presented at a conference), and may be found on an organisation or Society's website, as a journal, or as a special issue of journal.

In certain disciplines (such as computer science), conference papers may be highly regarded as a form of scholarly communication; the conferences are highly selective, the papers are generally peer reviewed, and papers are published in proceedings affiliated with high-quality publishing houses.

Conference papers may be indexed in a range of scholarly databases. If you only want to see conference papers, database limits can be used to filter results, or try a specific index such as the examples below:

• Conference proceedings citation index. Social science & humanities (CPCI-SSH)
• Conference proceedings citation index. Science (CPCI-S)
• ASME digital library conference proceedings

Honours students and postgraduates may request an Interlibrary Loan of a conference paper. However, conference paper requests may take longer than traditional article requests as they can be difficult to locate; they may have been only supplied to attendees or not formally published. Sometimes only the abstract is available.

If you are specifically looking for statistical data, try searching for the keyword statistics in a Google Advanced Search and limiting by a relevant site or domain. Below are some examples of sites, or you can try a domain such as .gov for government websites.

Statistical data can be found in the following selected sources:

• Australian Bureau of Statistics
• World Health Organization: Health Data and statistics
• Higher Education Statistics
• UNESCO Institute for Statistics
• Tourism Australia Statistics

For a list of databases that include statistics see: Databases by Subject: Statistics .

If you are specifically looking for information found in newspapers, the library has a large collection of Australian and overseas newspapers, both current and historical.

See the newspapers webpage , or the Newspapers subject guide for comprehensive information on newspaper sources, as well as searching tips, online videos and more.

Dissertations and theses

The Theses subject guide provides resources and guidelines for locating and accessing theses (dissertations) produced by Monash University as well as other universities in Australia and internationally.

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Conducting a literature review: how to find "the literature".

• Why Do A Literature Review?
• How To Find "The Literature"
• Found it -- Now What?

Finding The Literature

Research literature is vast. In the English language alone, over 2.5 million articles are published in peer reviewed journals each year . Sifting through the books and journals to find the most relevant research is challenging, but some of the resources on this page can help you.

To start, write down your research question and think about all the ways it could be described. (A thesaurus - online or in a database , can be helpful!) Think about the approach you are taking -- are you looking at it through the lens of Social Work? Is it also related to other fields, for example, Public Health, Education, Ethnic Studies? What research methods will you use -- how will you research the problem, or evaluate the intervention or policy to address it?

Subject Databases Can Help Find Articles

Powerful features vary by database, but many include the ability to:

• Combine search terms using AND and OR
• Search for exact phrases by using quotation marks " "
• Use controlled vocabulary (Thesaurus)
• Find material organized within a discipline -- law or policy, for example.
• Search by "fields" such as author, journal name, title
• Restrict by the age of  the subject (infants vs. very old)
• Limit by research method (including literature reviews!)

Snowballing aka Citation Slogging

If an article is relevant to your topic, you want to look at the research it cited ( backward citation ). But it can also be very helpful to see who has cited it ( forward citation ). There are several different ways to do this, and the results will overlap --  no single method is comprehensive.

Google Scholar  provides forward citations for some articles. It has a broader range of documents included (not just peer reviewed journals, but reports, pre-prints, etc.) and doesn't eliminate self citation or de-duplicate the results.

ISI Web of Science  contains the  Social Science Citation Index  which allows you to do a "Cited Reference" search. This shows other articles (from a prestigious list of peer reviewed journals) which have cited the target article, and it also shows the references for the the original article... both forward and backward citation.

Screenshot below on how to get to the Cited Reference Search from the  Social Science Citation Index .

Cited References From Within a Database

Using the Cited Reference Search

Oxford Bibliographies -- Great Starting Point for Social Welfare!

Oxford Bibliographies Online: Social Work  --  leading social work scholars identify the most important and significant sources in their areas, and UC-elinks gets you to the cited articles and books. 

Snowballing

http://hlwiki.slais.ubc.ca/index.php/Snowballing

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• URL: https://guides.lib.berkeley.edu/litreview

• UConn Library
• Literature Review: The What, Why and How-to Guide
• Introduction

Literature Review: The What, Why and How-to Guide — Introduction

• Getting Started
• How to Pick a Topic
• Strategies to Find Sources
• Evaluating Sources & Lit. Reviews
• Tips for Writing Literature Reviews
• Writing Literature Review: Useful Sites
• Citation Resources
• Other Academic Writings

What are Literature Reviews?

So, what is a literature review? "A literature review is an account of what has been published on a topic by accredited scholars and researchers. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (e.g., your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries." Taylor, D.  The literature review: A few tips on conducting it . University of Toronto Health Sciences Writing Centre.

Goals of Literature Reviews

What are the goals of creating a Literature Review?  A literature could be written to accomplish different aims:

• To develop a theory or evaluate an existing theory
• To summarize the historical or existing state of a research topic
• Identify a problem in a field of research 

Baumeister, R. F., & Leary, M. R. (1997). Writing narrative literature reviews .  Review of General Psychology , 1 (3), 311-320.

What kinds of sources require a Literature Review?

• A research paper assigned in a course
• A thesis or dissertation
• A grant proposal
• An article intended for publication in a journal

All these instances require you to collect what has been written about your research topic so that you can demonstrate how your own research sheds new light on the topic.

Types of Literature Reviews

What kinds of literature reviews are written?

Narrative review: The purpose of this type of review is to describe the current state of the research on a specific topic/research and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weakness, and gaps are identified. The review ends with a conclusion section which summarizes the findings regarding the state of the research of the specific study, the gaps identify and if applicable, explains how the author's research will address gaps identify in the review and expand the knowledge on the topic reviewed.

• Example : Predictors and Outcomes of U.S. Quality Maternity Leave: A Review and Conceptual Framework:  10.1177/08948453211037398  

Systematic review : "The authors of a systematic review use a specific procedure to search the research literature, select the studies to include in their review, and critically evaluate the studies they find." (p. 139). Nelson, L. K. (2013). Research in Communication Sciences and Disorders . Plural Publishing.

• Example : The effect of leave policies on increasing fertility: a systematic review:  10.1057/s41599-022-01270-w

Meta-analysis : "Meta-analysis is a method of reviewing research findings in a quantitative fashion by transforming the data from individual studies into what is called an effect size and then pooling and analyzing this information. The basic goal in meta-analysis is to explain why different outcomes have occurred in different studies." (p. 197). Roberts, M. C., & Ilardi, S. S. (2003). Handbook of Research Methods in Clinical Psychology . Blackwell Publishing.

• Example : Employment Instability and Fertility in Europe: A Meta-Analysis:  10.1215/00703370-9164737

Meta-synthesis : "Qualitative meta-synthesis is a type of qualitative study that uses as data the findings from other qualitative studies linked by the same or related topic." (p.312). Zimmer, L. (2006). Qualitative meta-synthesis: A question of dialoguing with texts .  Journal of Advanced Nursing , 53 (3), 311-318.

• Example : Women’s perspectives on career successes and barriers: A qualitative meta-synthesis:  10.1177/05390184221113735

Literature Reviews in the Health Sciences

• UConn Health subject guide on systematic reviews Explanation of the different review types used in health sciences literature as well as tools to help you find the right review type
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• Next: How to Pick a Topic >>
• Last Updated: Sep 21, 2022 2:16 PM
• URL: https://guides.lib.uconn.edu/literaturereview

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

Chapter 4: Where to Find the Literature

Learning objectives.

At the conclusion of this chapter, you will be able to:

• Search a library catalog to locate electronic and print books.
• Search databases to find scholarly articles, dissertations, and conference proceedings.
• Retrieve a copy or the full text of information sources
• Identify and locate core resources in your discipline or topic area

4.1 Overview of discovery

Discovery, or background research, is something that happens at the beginning of the research process when you are just learning about a topic. It is a search for general information to get the big picture of a topic for exploration, ideas about subtopics and context for the actual focused research you will do later. It is also a time to build a list of distinctive, broad, narrow, and related search terms.

Discovery happens again when you are ready to focus in on your research question and begin your own literature review. There are two crucial elements to discovering the literature for your review with the least amount of stress as possible: the places you look and the words you use in your search .

The places you look depend on:

• The stage you are in your research
• The disciplines represented in your research question
• The importance of currency in your research topic

Review the information and publication cycles discussed in Chapter 2 to put those sources of this information in context.

The words you use will help you locate existing literature on your topic, as well as topics that may be closely related to yours. There are two categories for these words:

• Keywords – the natural language terms we think of when we discuss and read about a topic
• Subject terms – the assigned vocabulary for a catalog or database

The words you use during both the initial and next stage of discovery should be recorded in some way throughout the literature search process. Additional terms will come to light as you read and as your question becomes more specific. You will want to keep track of those words and terms, as they will be useful in repeating your searches in additional databases, catalogs, and other repositories. Later in this chapter, we will discuss how putting the two elements (the places we look and the words we use) together can be enhanced by the use of Boolean operators and discipline-specific thesauri.

Discovery is an iterative process. There is not a straight, bright line from beginning to end. You will go back into the literature throughout the writing of your literature review as you uncover gaps in the evidence and as additional questions arise.

4.2 Finding sources: Places to look

Let’s take some time to look at where the information sources you need for your literature review are located, indexed, and stored. At this stage, you have a general idea of your research area and have done some background searching to learn the scope and the context of your topic. You have begun collecting keywords to use in your later searching. Now, as you focus in on your literature review topic, you will take your searches to the databases and other repositories to see what the other researchers and scholars are saying about the topic.

The following resources are ordered from the more general and established information to the more recent and specific. Although it is possible to find some of these resources by searching the open web, using a search engine like Google or Google Scholar, this is not the most efficient or effective way to search for and discover research material. As a result, most of the resources described in this section are found from within academic library catalogs and databases, rather than internet search engines.

4.2.1 Finding books and ebooks

4.2.1.1 books.

Look to books for broad and general information that is useful for background research. Books are “essential guides to understanding theory and for helping you to validate the need for your study, confirm your choice of literature, and certify (or contradict) its findings.” ( Fink, 4th ed., 2014, p. 77 ). In this section, we will consider print and electronic books as well as print and electronic encyclopedias.

Most academic libraries use the Library of Congress classification system to organize their books and other resources. The Library of Congress classification system divides a library’s collection into 21 classes or categories. A specific letter of the alphabet is assigned to each class. More detailed divisions are accomplished with two and three letter combinations. Book shelves in most academic libraries are marked with a Library of Congress letter-number combination to correspond to the Library of Congress letter-number combination on the spines of library materials. This is often referred to as a call number and it is noted in the catalog record of every physical item on the library shelves. ( Bennard et al, 2014a )

The Library of Congress (LC) classification for Education (General) is L7-991, with LA, LB, LC, LD, LE, LG, LH, LJ, and LT subclasses. For example,

LB3012.2.L36 1995 Beyond the Schoolhouse Gate: Free Speech and the Inculcation of Values

In Nursing, the LC subject range is RT1-120. A book with this LC call number might look like: R121.S8 1990 Stedman’s Medical Dictionary . Areas related to nursing that are outside that range include:

R121 Medical dictionaries

R726.8 Hospice care

R858-859.7 Medical informatics

RB37 Diagnostic and laboratory tests

RB115 Nomenclature (procedural coding – CPT, ICD9)

RC69-71 Diagnosis

RC86.7 Emergency medicine

RC266 Oncology nursing

RC952-954.6 Geriatrics

RD93-98 Wound care

RD753 Orthopedic nursing

RG951 Maternal child nursing / Obstetrical nursing

RJ245 Pediatric nursing

RM216 Nutrition and diet therapy

RM301.12 Drug guides

In most libraries, there is a collection of reference material kept in a specific section. These books, consisting of encyclopedias, dictionaries, thesauri, handbooks, atlases, and other material contain useful background or overview information about topics. Ask the librarian for help in finding an appropriate reference book. Although reference material can only be used in the library, other print books will likely be in what’s called the “circulating collection,” meaning they are available to check out.

4.2.1.2 Ebooks

The library also provides access to electronic reference material. Some are subject specific and others are general reference sources. Although each resource will have a different “look” just as different print encyclopedias and dictionaries look different, each should have a search box. Most will have a table of contents for navigation within the work. Content includes pages of text in books and encyclopedias and occasionally, videos. In all cases you will be able to collect background information and search terms to use later.

North American academic libraries buy or subscribe to individual ebook titles as well as collections of ebooks. Ebooks appear on various publisher and platforms, such as Springer, Cambridge, ebrary (ProQuest), EBSCO, and Safari to name a few. Although access to these ebooks varies by platform, you can find the ebook titles your library has access to through the library catalog. You can generally read the entire book online, and you can often download single chapters or a limited number of pages. You may be able to download an entire ebook without restrictions, or you may have to ‘check it out’ for a limited period of time. Some downloads will be in PDF format, others use another type of free ebook viewing software, like ePUB. Unlike public library ebook collections, most academic library ebooks are not be downloadable to ereader devices, such as Amazon’s Kindle

4.2.1.3 The Library Catalog

In general, everything owned or licensed by a library is indexed in “the library catalog”. Although most library catalogs are now sophisticated electronic products called ‘integrated library systems’, they began as wooden card filing cabinets where researchers could look for books by author, title, or subject.

While the look and feel of current integrated library systems vary between libraries, they operate in similar ways. Most library catalogs are quickly found from a library’s home page or website. The library catalog is the quickest way to find books and ebooks on your topic.

Here are some general tips for locating books in a library catalog:

• Use the search box generally found on a library’s home page to start a search.
• Type a book title, author name, or subject keywords into the search box.
• You will be directed to a results page.
• If you click on a book title or see an option to see more details about the book, you can look at its full bibliographic record, which provides more information about the book, as well as where to find the book. Pay particular attention to subjects associated with the item, adding relevant and appropriate terms to your list of search terms for future use.
• Look for an “Advanced Search” option near the basic or single search box
• Publication Year
• Call number
• There is generally a “Format” list on the advanced search page screen. This list will give you options for limiting format to Print Books or Ebooks.
• You can limit searches to a specific library or libraries to narrow by location or ‘search everything’ to broaden your search.

OCLC WorldCat ( https://www.worldcat.org/ ) is the world’s largest network of library content and it provides another way to search for books and ebooks. For students who do not have immediate access to an academic library catalog, WorldCat is a way to search many library catalogs at once for an item and then locate a library near you that may own or subscribe to it. Whether you will be able check the item out, request it, place an interlibrary loan request for it, or have it shipped will depend on local library policy. Note that like your own library catalog, WorldCat has a single search box, an Advanced search feature, and a way to limit by format and location.

4.2.2 Finding scholarly articles

While books and ebooks provide good background information on your topic, the main body of the literature in your research area will be found in academic journals. Scholarly journals are the main forum for research publication. Unlike books and professional magazines that may comment or summarize research findings, articles in scholarly journals are written by a researcher or research team. These authors will report in detail original study findings, and will include the data used. Articles in academic journals also go through a screening or peer-review process before publication,implying a higher level of quality and reliability. For the most current, authoritative information on a topic, scholars and researchers look to the published, scholarly literature. That said,

Journals, and the articles they contain, are often quite expensive. Libraries spend a large part of their collection budget subscribing to journals in both print and online formats. You may have noticed that a Google Scholar search will provide the citation to a journal article but will not link to the full text. This happens because Google does not subscribe to journals. It only searches and retrieves freely available web content. However, libraries do subscribe to journals and have entered into agreements to share their journal and book collections with other libraries. If you are affiliated with a library as a student, staff, or faculty member, you have access to many other libraries’ resources, through a service called interlibrary loan. Do not pay the large sums required to purchase access to articles unless you do not have another way to obtain the material, and you are unable to find a substitute resource that provides the information you need. ( Bennard et al, 2014 a)

4.2.2.1 Databases

A database is an electronic system for organizing information. Journal databases are where the scholarly articles are organized and indexed for searching. Anyone with an internet connection has free access to public databases such as PubMed and ERIC. Students can also search in library-subscribed general information databases (such as EBSCO’s Academic Search Premier) or a specialized or subject specific database (for example, a ProQuest version of CINAHL for Nursing or ERIC for Education).

Library databases store and display different types of information sets than a library catalog or Google Scholar. There are different types of databases that include:

• Indexes– with citations only
• Abstract databases – with citations and abstracts only
• Full text databases – with citations and the full text of articles, reports, and other materials

Library databases are often connected to each other by means of a “link resolver”, allowing different databases to “talk to each other.” For example, if you are searching an index database and discover an article you want to read in its entirety, you can click on a link resolver that takes you to another database where the full-text of the article is held. If the full-text is not available, an automated form to request the item from another library may be an option.

Why search a database instead of Google Scholar or your library catalog? Both can lead you to good articles BUT:

• The content is wide-ranging but not comprehensive or as current as a database that may be updated daily.
• Google Scholar doesn’t disclose its criteria for what makes the results “scholarly’ and search results often vary in quality and availability.
• Neither gives you as much control over your search as you get in a database.

4.2.2.2 Citation searches

Another way to find additional books and articles on your topic is to mine the reference lists of books and articles you already found. By tracing literature cited in published titles, you not only add to your understanding of the scholarly conversation about your research topic but also enrich your own literature search.

A citation is a reference to an item that gives enough information for you to identify it and find it again if necessary. You can use the citations in the material you found to lead you to other resources. Generally, citations include four elements:

For example,

For a good summary of how to read a citation for a book, book chapter, and journal article in both APA and MLA format, see this explanation   at: https://www.slideshare.net/opensunytextbooks/gathering-components-of-a-citation

4.2.3 Finding conference papers

Conference papers are often overlooked because they can be difficult to locate in full-text. Sometimes the papers from an annual proceeding are treated like an individual book, or a single special issue of a journal. Sometimes the papers from a conference are not published and must be requested from the original author. Despite publication inconsistency, conference papers may be the first place a scholar presents important findings and, as such, are relevant to your own research. Places to look for conference papers:

4.2.3.1 WorldCat

• use keywords from the conference name (NOT the article title)
• it often helps to leave out terms like: conference, proceedings, transactions, congresses, symposia/symposium, exposition, workshop or meeting
• include the year of the conference
• include the city in which the conference took place

4.2.3.2 Google Scholar

• Search by keyword and add the word ‘conference’ and the year to your search, for example: ‘conference education 2008′

4.2.3.3 Databases

• For Education: ERIC, limit to ‘Collected Works–Proceedings’ or ‘Speeches/Meeting papers’
• For Nursing: CINAHL, limit to proceedings in the “Publication Type” box
• For Education: Education Full Text, limit to ‘proceeding’ in the “Document Type” box
• PsychInfo: limit to ‘Conference Proceedings’ in the “Record Type” Box
• Web of Science: limit to ‘conference’

4.2.3.4 Professional Societies & Other Sponsoring Organizations

Check the web sites of the organizations that sponsor conferences. Listings of conference proceedings are often under a “Publications” or “Meetings” tab/link. The National Library of Medicine maintains a conference proceedings subject guide for health-related national and international conferences. Though many papers/proceedings are not available for free, the organization web site will often contain citations of proceedings that you can request through interlibrary loan.

4.2.4 Finding dissertations

In addition to journal articles, original research is also published in books, reports, conference proceedings, theses and dissertations. Both theses and dissertations are very detailed and comprehensive accounts of research work. Dissertations and theses are a primary source of original research and include “referencing, both in text and in the reference list, so that, in principle, any reference to the literature may be easily traced and followed up.” ( Wallace & Wray, p. 187 ). Citation searching of the reference list or bibliography in a dissertation is another method for discovering the relevant literature for your own research area. Like conference papers, they are more difficult to locate and retrieve than books and articles. Some may be available electronically in full-text at no cost. Others may only be available to the affiliates of the university or college where a degree was granted. Others are behind paywalls and can only be accessed after purchasing. Both CINAHL and ERIC index dissertations. Individual universities and institutional repositories often list dissertations held locally. Other places to look for theses and dissertations include:

Dissertations Express – search for dissertations from around the world. Search by subject or keyword, results include author, title, date, and where the degree was granted. Some are available in full-text at no cost, however most requirement payment.

EThOS – the national thesis service for the United Kingdom, managed by the British Library. It is a national aggregated record of all doctoral theses awarded by UK Higher Education institutions, providing free access to the full text of many theses for use by all researchers to further their own study.

Theses Canada – a collaborative program between Library and Archives Canada (LAC) and nearly 70 accredited Canadian universities. The collection contains both microfiche and electronic theses and dissertations that are for personal or academic research purposes.

4.3 Advanced searching

Now that you have an idea of some of the places to look for information on your research topic and the form that information takes (books, ebooks, journals, conference papers, and dissertations), it’s time to consider not only how to use the specialized resources for your discipline but how to get the most out of those resources. To do a graduate-level literature review and find everything published on your topic, advanced search and retrieval skills are needed.

4.3.1 Search Operators

Literature review research often necessitates the use of Boolean operators to combine keywords. The operators – AND, OR, and NOT — are powerful tools for searching in a database or search engine. By using a combination of terms and one or more Boolean operator, you can focus your search and narrow your search results to a more specific area than a basic keyword search allows.

Boolean operators – allow you to combine your search terms using the keywords AND , OR and NOT . Look at the diagrams in Figure 4.6 to see how these terms will affect your results.

Truncation – If you use truncation (or wildcards), your search results will contain documents including variations of that term.

For example: light* will retrieve, of course, light , but also terms like: lighting , lightning , lighters and lights . Note that the truncation symbol varies depending on where you search. The most common truncation symbols are the asterisk (*) and question mark (?).

Phrase searching – Phrase searching is used to make sure your search retrieves a specific concept. For example “ durable wood products ” will retrieve more relevant documents than the same terms without quotation marks.

For a description of these more advanced search features, watch this short video tutorial on effective search strategies. ( Clark, 2016 ).

4.3.2 Finding sources in your discipline or topic area

It’s time to put these tips and your search skills to use. This is the point, if you have not done so already, to talk to a librarian. The librarian will direct you to the resources you need, including research databases to which the library subscribes, for your discipline or subject area. Literature reviews rely heavily on data from online databases, such as CINAHL for Nursing and ERIC for Education. Unfortunately, the costs to subscribe to vendor-provided products is high. Students affiliated with large university libraries that can afford to subscribe to these products will have access to many databases, while those who do not have fewer options.

Students who do not have access to subscription databases such as CINAHL or ERIC through Ebsco and ProQuest should use PubMed for Nursing at https://www.ncbi.nlm.nih.gov/pubmed/ and the public version of ERIC at https://eric.ed.gov/ for literature review research.

Although a librarian is the best resource for learning how to use a specific tool, an online tutorial on how to search PubMed may be useful and informative for those who do not have access to a librarian or a subscription database: Likewise, this document, titled “ How does the ERIC search work ,” provided by the Institute of Education Sciences provides some helpful tips for searching the public version ERIC.

4.3.3 Specialized vocabulary

One major source of search terms in a database is a specialized dictionary, or thesaurus, used to index journal articles. Thesauri provide a consistent and standardized way to retrieve information, especially when different terms are used for the same concept. According to Fink ( 2014 ), “evidence exists that using thesaurus terms produces more of the available citations than does reliance on key words…Using the appropriate subject heading will enable the reviewer to find all citations regardless of how the author uses the term.” (p. 24).

In Education and Nursing, thesauri are available. In subscription databases, as well as in PubMed and the public version of ERIC, look for the thesaurus to guide you to appropriate and relevant subject terms.

4.3.4 Citation Searching

Citation searching works best when you already have a relevant work that is on topic. From the document you identified as useful for your own literature review, you can either search citations forward or backward to gather additional resources. Cited reference searching and reference or bibliography mining are advanced search techniques that may also help generate new ideas as well as additional keywords and subject areas.

For cited reference searching, use Google Scholar or library databases such as Web of Science or Scopus. These tools trace citations forward to link to newly published books, journal articles, book chapters, and reports that were written after the document you found. Through cited reference searching, you may also locate works that have been cited numerous times, indicating what may be a seminal work in your field.

With citation mining, you will look at the references or works cited list in the resource you located to identify other relevant works. In this type of search, you will be tracing citations backward to find significant books, journal articles, book chapters, and reports that were written before the document you found. For a brief discussion about citation searching , check out this article by Hammond & Brown ( 2008 ).

The two most important finding tools you will use are a library catalog and databases. Looking for information in catalogs and databases takes practice.

Get started by setting aside some dedicated time to become familiar with the process:

• Practice by locating one reference book and one ebook in your library catalog or WorldCat
• Practice searching in freely available databases such as PubMed or ERIC
• Try some of the limiters to see what each does to your search results
• Once you find an article, what do you need to do to get it in full-text?
• Find out how to use interlibrary loan or document delivery.

Next, complete this exercise:

• Browse through a popular or scientific publication such as the science section of the New York Times or Scientific American . Find a short article that looks interesting and is easy to understand.
• an article that reports on a recent study published in a scholarly journal;
• the title of the journal;
• the name of the author(s); and
• an indication of when the original study appeared. Note: sometimes the source will say that the research was published in a latest issue of Science or Nature .
• Once you find some of these facts (journal title and the authors should be sufficient), you can start to search for the primary source in a library catalog or the library’s databases.
• Catalog search: find out if your school subscribes to a particular journal by searching for the journal by title.
• Electronic subscription—great! It means you can access the journal right away. Once you get to the online (or electronic) version of the journal, you are given a choice of searching within this publication. An author search should be sufficient to locate the article.
• Print subscription version—good! You can search in databases or a discovery service tool for your article by entering the journal title and the authors. Once you locate a record about the article, which will include volume and issue number, page numbers, the article title, you can go to the shelves where you will find the issue of the journal that includes your article.
• Microform version—still good! Again, after searching databases and locating the exact information about the article, you should be able to locate the appropriate microfilm reel or microfiche. Before the widespread and easy access to online versions of materials, microforms were used to save space by preserving documents on film. Libraries are equipped with microform readers—if you need help using a reader, ask the library staff. ( Bennard et al, 2014b )

Test Yourself

Get an article.

• Access PubMed or ERIC
• Do a subject search, using the thesaurus (for ERIC) or MeSH terms (for PubMed)
• Do a keyword search
• Supplement your subject search with keywords, using advanced search tools like Boolean operators, truncation, or phrase searching
• Limit your search by language, date of publication or PICO factor
• Access the full text of an article you find.
• If full text is not available, find out how to request the article through interlibrary loan

In your general topic area, do you know:

• The core source materials?
• The most significant theories?
• The major issues and debates surrounding your topic area?
• The key political, social, economic, legal, environmental, and/or technological aspects of your topic?
• The origins of your topic?
• The definitions for your topic?
• How knowledge in your topic area is organized?
• What problems or solutions have been addressed to date?
• If you don’t know the answers to these questions, do you know how to find the answers?

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Literature Reviews for Education and Nursing Graduate Students Copyright © by Linda Frederiksen is licensed under a Creative Commons Attribution 4.0 International License , except where otherwise noted.

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Writing a Literature Review

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A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

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Does your assignment or publication require that you write a literature review? This guide is intended to help you understand what a literature is, why it is worth doing, and some quick tips composing one.

Understanding Literature Reviews

What is a literature review  .

Typically, a literature review is a written discussion that examines publications about  a particular subject area or topic. Depending on disciplines, publications, or authors a literature review may be: 

A summary of sources An organized presentation of sources A synthesis or interpretation of sources An evaluative analysis of sources

A Literature Review may be part of a process or a product. It may be:

A part of your research process A part of your final research publication An independent publication

Why do a literature review?

The Literature Review will place your research in context. It will help you and your readers:  

Locate patterns, relationships, connections, agreements, disagreements, & gaps in understanding Identify methodological and theoretical foundations Identify landmark and exemplary works Situate your voice in a broader conversation with other writers, thinkers, and scholars

The Literature Review will aid your research process. It will help you to:

Establish your knowledge Understand what has been said Define your questions Establish a relevant methodology Refine your voice Situate your voice in the conversation

What does a literature review look like?

The Literature Review structure and organization may include sections such as:  

An introduction or overview A body or organizational sub-divisions A conclusion or an explanation of significance

The body of a literature review may be organized in several ways, including:

Chronologically: organized by date of publication Methodologically: organized by type of research method used Thematically: organized by concept, trend, or theme Ideologically: organized by belief, ideology, or school of thought

• Find a focus
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Additional Sources

• Reviewing the literature. Project Planner.
• Literature Review: By UNC Writing Center
• PhD on Track
• CU Graduate Students Thesis & Dissertation Guidance
• CU Honors Thesis Guidance

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• URL: https://libguides.colorado.edu/strategies/litreview
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Organizing Your Social Sciences Research Paper

• 5. The Literature Review
• Purpose of Guide
• Design Flaws to Avoid
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• Glossary of Research Terms
• Reading Research Effectively
• Narrowing a Topic Idea
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• Further Readings
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• Bibliography

A literature review surveys prior research published in books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated. Literature reviews are designed to provide an overview of sources you have used in researching a particular topic and to demonstrate to your readers how your research fits within existing scholarship about the topic.

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . Fourth edition. Thousand Oaks, CA: SAGE, 2014.

Importance of a Good Literature Review

A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories . A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that informs how you are planning to investigate a research problem. The analytical features of a literature review might:

• Give a new interpretation of old material or combine new with old interpretations,
• Trace the intellectual progression of the field, including major debates,
• Depending on the situation, evaluate the sources and advise the reader on the most pertinent or relevant research, or
• Usually in the conclusion of a literature review, identify where gaps exist in how a problem has been researched to date.

Given this, the purpose of a literature review is to:

• Place each work in the context of its contribution to understanding the research problem being studied.
• Describe the relationship of each work to the others under consideration.
• Identify new ways to interpret prior research.
• Reveal any gaps that exist in the literature.
• Resolve conflicts amongst seemingly contradictory previous studies.
• Identify areas of prior scholarship to prevent duplication of effort.
• Point the way in fulfilling a need for additional research.
• Locate your own research within the context of existing literature [very important].

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper. 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . Los Angeles, CA: SAGE, 2011; Knopf, Jeffrey W. "Doing a Literature Review." PS: Political Science and Politics 39 (January 2006): 127-132; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012.

Types of Literature Reviews

It is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the primary studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally among scholars that become part of the body of epistemological traditions within the field.

In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews. Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are a number of approaches you could adopt depending upon the type of analysis underpinning your study.

Argumentative Review This form examines literature selectively in order to support or refute an argument, deeply embedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to make summary claims of the sort found in systematic reviews [see below].

Integrative Review Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses or research problems. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication. This is the most common form of review in the social sciences.

Historical Review Few things rest in isolation from historical precedent. Historical literature reviews focus on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review A review does not always focus on what someone said [findings], but how they came about saying what they say [method of analysis]. Reviewing methods of analysis provides a framework of understanding at different levels [i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques], how researchers draw upon a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection, and data analysis. This approach helps highlight ethical issues which you should be aware of and consider as you go through your own study.

Systematic Review This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyze data from the studies that are included in the review. The goal is to deliberately document, critically evaluate, and summarize scientifically all of the research about a clearly defined research problem . Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?" This type of literature review is primarily applied to examining prior research studies in clinical medicine and allied health fields, but it is increasingly being used in the social sciences.

Theoretical Review The purpose of this form is to examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review helps to establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

NOTE: Most often the literature review will incorporate some combination of types. For example, a review that examines literature supporting or refuting an argument, assumption, or philosophical problem related to the research problem will also need to include writing supported by sources that establish the history of these arguments in the literature.

Baumeister, Roy F. and Mark R. Leary. "Writing Narrative Literature Reviews."  Review of General Psychology 1 (September 1997): 311-320; Mark R. Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147; Petticrew, Mark and Helen Roberts. Systematic Reviews in the Social Sciences: A Practical Guide . Malden, MA: Blackwell Publishers, 2006; Torracro, Richard. "Writing Integrative Literature Reviews: Guidelines and Examples." Human Resource Development Review 4 (September 2005): 356-367; Rocco, Tonette S. and Maria S. Plakhotnik. "Literature Reviews, Conceptual Frameworks, and Theoretical Frameworks: Terms, Functions, and Distinctions." Human Ressource Development Review 8 (March 2008): 120-130; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

Structure and Writing Style

I.  Thinking About Your Literature Review

The structure of a literature review should include the following in support of understanding the research problem :

• An overview of the subject, issue, or theory under consideration, along with the objectives of the literature review,
• Division of works under review into themes or categories [e.g. works that support a particular position, those against, and those offering alternative approaches entirely],
• An explanation of how each work is similar to and how it varies from the others,
• Conclusions as to which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of their area of research.

The critical evaluation of each work should consider :

• Provenance -- what are the author's credentials? Are the author's arguments supported by evidence [e.g. primary historical material, case studies, narratives, statistics, recent scientific findings]?
• Methodology -- were the techniques used to identify, gather, and analyze the data appropriate to addressing the research problem? Was the sample size appropriate? Were the results effectively interpreted and reported?
• Objectivity -- is the author's perspective even-handed or prejudicial? Is contrary data considered or is certain pertinent information ignored to prove the author's point?
• Persuasiveness -- which of the author's theses are most convincing or least convincing?
• Validity -- are the author's arguments and conclusions convincing? Does the work ultimately contribute in any significant way to an understanding of the subject?

II.  Development of the Literature Review

Four Basic Stages of Writing 1.  Problem formulation -- which topic or field is being examined and what are its component issues? 2.  Literature search -- finding materials relevant to the subject being explored. 3.  Data evaluation -- determining which literature makes a significant contribution to the understanding of the topic. 4.  Analysis and interpretation -- discussing the findings and conclusions of pertinent literature.

Consider the following issues before writing the literature review: Clarify If your assignment is not specific about what form your literature review should take, seek clarification from your professor by asking these questions: 1.  Roughly how many sources would be appropriate to include? 2.  What types of sources should I review (books, journal articles, websites; scholarly versus popular sources)? 3.  Should I summarize, synthesize, or critique sources by discussing a common theme or issue? 4.  Should I evaluate the sources in any way beyond evaluating how they relate to understanding the research problem? 5.  Should I provide subheadings and other background information, such as definitions and/or a history? Find Models Use the exercise of reviewing the literature to examine how authors in your discipline or area of interest have composed their literature review sections. Read them to get a sense of the types of themes you might want to look for in your own research or to identify ways to organize your final review. The bibliography or reference section of sources you've already read, such as required readings in the course syllabus, are also excellent entry points into your own research. Narrow the Topic The narrower your topic, the easier it will be to limit the number of sources you need to read in order to obtain a good survey of relevant resources. Your professor will probably not expect you to read everything that's available about the topic, but you'll make the act of reviewing easier if you first limit scope of the research problem. A good strategy is to begin by searching the USC Libraries Catalog for recent books about the topic and review the table of contents for chapters that focuses on specific issues. You can also review the indexes of books to find references to specific issues that can serve as the focus of your research. For example, a book surveying the history of the Israeli-Palestinian conflict may include a chapter on the role Egypt has played in mediating the conflict, or look in the index for the pages where Egypt is mentioned in the text. Consider Whether Your Sources are Current Some disciplines require that you use information that is as current as possible. This is particularly true in disciplines in medicine and the sciences where research conducted becomes obsolete very quickly as new discoveries are made. However, when writing a review in the social sciences, a survey of the history of the literature may be required. In other words, a complete understanding the research problem requires you to deliberately examine how knowledge and perspectives have changed over time. Sort through other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to explore what is considered by scholars to be a "hot topic" and what is not.

III.  Ways to Organize Your Literature Review

Chronology of Events If your review follows the chronological method, you could write about the materials according to when they were published. This approach should only be followed if a clear path of research building on previous research can be identified and that these trends follow a clear chronological order of development. For example, a literature review that focuses on continuing research about the emergence of German economic power after the fall of the Soviet Union. By Publication Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on environmental studies of brown fields if the progression revealed, for example, a change in the soil collection practices of the researchers who wrote and/or conducted the studies. Thematic [“conceptual categories”] A thematic literature review is the most common approach to summarizing prior research in the social and behavioral sciences. Thematic reviews are organized around a topic or issue, rather than the progression of time, although the progression of time may still be incorporated into a thematic review. For example, a review of the Internet’s impact on American presidential politics could focus on the development of online political satire. While the study focuses on one topic, the Internet’s impact on American presidential politics, it would still be organized chronologically reflecting technological developments in media. The difference in this example between a "chronological" and a "thematic" approach is what is emphasized the most: themes related to the role of the Internet in presidential politics. Note that more authentic thematic reviews tend to break away from chronological order. A review organized in this manner would shift between time periods within each section according to the point being made. Methodological A methodological approach focuses on the methods utilized by the researcher. For the Internet in American presidential politics project, one methodological approach would be to look at cultural differences between the portrayal of American presidents on American, British, and French websites. Or the review might focus on the fundraising impact of the Internet on a particular political party. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Other Sections of Your Literature Review Once you've decided on the organizational method for your literature review, the sections you need to include in the paper should be easy to figure out because they arise from your organizational strategy. In other words, a chronological review would have subsections for each vital time period; a thematic review would have subtopics based upon factors that relate to the theme or issue. However, sometimes you may need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. However, only include what is necessary for the reader to locate your study within the larger scholarship about the research problem.

Here are examples of other sections, usually in the form of a single paragraph, you may need to include depending on the type of review you write:

• Current Situation : Information necessary to understand the current topic or focus of the literature review.
• Sources Used : Describes the methods and resources [e.g., databases] you used to identify the literature you reviewed.
• History : The chronological progression of the field, the research literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
• Selection Methods : Criteria you used to select (and perhaps exclude) sources in your literature review. For instance, you might explain that your review includes only peer-reviewed [i.e., scholarly] sources.
• Standards : Description of the way in which you present your information.
• Questions for Further Research : What questions about the field has the review sparked? How will you further your research as a result of the review?

IV.  Writing Your Literature Review

Once you've settled on how to organize your literature review, you're ready to write each section. When writing your review, keep in mind these issues.

Use Evidence A literature review section is, in this sense, just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence [citations] that demonstrates that what you are saying is valid. Be Selective Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the research problem, whether it is thematic, methodological, or chronological. Related items that provide additional information, but that are not key to understanding the research problem, can be included in a list of further readings . Use Quotes Sparingly Some short quotes are appropriate if you want to emphasize a point, or if what an author stated cannot be easily paraphrased. Sometimes you may need to quote certain terminology that was coined by the author, is not common knowledge, or taken directly from the study. Do not use extensive quotes as a substitute for using your own words in reviewing the literature. Summarize and Synthesize Remember to summarize and synthesize your sources within each thematic paragraph as well as throughout the review. Recapitulate important features of a research study, but then synthesize it by rephrasing the study's significance and relating it to your own work and the work of others. Keep Your Own Voice While the literature review presents others' ideas, your voice [the writer's] should remain front and center. For example, weave references to other sources into what you are writing but maintain your own voice by starting and ending the paragraph with your own ideas and wording. Use Caution When Paraphrasing When paraphrasing a source that is not your own, be sure to represent the author's information or opinions accurately and in your own words. Even when paraphrasing an author’s work, you still must provide a citation to that work.

V.  Common Mistakes to Avoid

These are the most common mistakes made in reviewing social science research literature.

• Sources in your literature review do not clearly relate to the research problem;
• You do not take sufficient time to define and identify the most relevant sources to use in the literature review related to the research problem;
• Relies exclusively on secondary analytical sources rather than including relevant primary research studies or data;
• Uncritically accepts another researcher's findings and interpretations as valid, rather than examining critically all aspects of the research design and analysis;
• Does not describe the search procedures that were used in identifying the literature to review;
• Reports isolated statistical results rather than synthesizing them in chi-squared or meta-analytic methods; and,
• Only includes research that validates assumptions and does not consider contrary findings and alternative interpretations found in the literature.

Cook, Kathleen E. and Elise Murowchick. “Do Literature Review Skills Transfer from One Course to Another?” Psychology Learning and Teaching 13 (March 2014): 3-11; Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . London: SAGE, 2011; Literature Review Handout. Online Writing Center. Liberty University; Literature Reviews. The Writing Center. University of North Carolina; Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: SAGE, 2016; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012; Randolph, Justus J. “A Guide to Writing the Dissertation Literature Review." Practical Assessment, Research, and Evaluation. vol. 14, June 2009; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016; Taylor, Dena. The Literature Review: A Few Tips On Conducting It. University College Writing Centre. University of Toronto; Writing a Literature Review. Academic Skills Centre. University of Canberra.

Writing Tip

Break Out of Your Disciplinary Box!

Thinking interdisciplinarily about a research problem can be a rewarding exercise in applying new ideas, theories, or concepts to an old problem. For example, what might cultural anthropologists say about the continuing conflict in the Middle East? In what ways might geographers view the need for better distribution of social service agencies in large cities than how social workers might study the issue? You don’t want to substitute a thorough review of core research literature in your discipline for studies conducted in other fields of study. However, particularly in the social sciences, thinking about research problems from multiple vectors is a key strategy for finding new solutions to a problem or gaining a new perspective. Consult with a librarian about identifying research databases in other disciplines; almost every field of study has at least one comprehensive database devoted to indexing its research literature.

Frodeman, Robert. The Oxford Handbook of Interdisciplinarity . New York: Oxford University Press, 2010.

Another Writing Tip

Don't Just Review for Content!

While conducting a review of the literature, maximize the time you devote to writing this part of your paper by thinking broadly about what you should be looking for and evaluating. Review not just what scholars are saying, but how are they saying it. Some questions to ask:

• How are they organizing their ideas?
• What methods have they used to study the problem?
• What theories have been used to explain, predict, or understand their research problem?
• What sources have they cited to support their conclusions?
• How have they used non-textual elements [e.g., charts, graphs, figures, etc.] to illustrate key points?

When you begin to write your literature review section, you'll be glad you dug deeper into how the research was designed and constructed because it establishes a means for developing more substantial analysis and interpretation of the research problem.

Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1 998.

Yet Another Writing Tip

When Do I Know I Can Stop Looking and Move On?

Here are several strategies you can utilize to assess whether you've thoroughly reviewed the literature:

• Look for repeating patterns in the research findings . If the same thing is being said, just by different people, then this likely demonstrates that the research problem has hit a conceptual dead end. At this point consider: Does your study extend current research?  Does it forge a new path? Or, does is merely add more of the same thing being said?
• Look at sources the authors cite to in their work . If you begin to see the same researchers cited again and again, then this is often an indication that no new ideas have been generated to address the research problem.
• Search Google Scholar to identify who has subsequently cited leading scholars already identified in your literature review [see next sub-tab]. This is called citation tracking and there are a number of sources that can help you identify who has cited whom, particularly scholars from outside of your discipline. Here again, if the same authors are being cited again and again, this may indicate no new literature has been written on the topic.

Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: Sage, 2016; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

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Literature Review

Find sources, finding books, finding articles, search citators.

• 2. Evaluate Sources
• 3. Organize Information

Be selective when choosing sources to include in your review.

Start by looking for documents that highlight major developments and theories on a topic. Look for documents that generated significant contributions to the field of study. Ensure coverage of all sides of the topic.

A good strategy is to start with the most recently published sources on your topic and search backwards. Recent studies will mention major crossroads and developments in the field, more recently and often historically. Depending on your topic, your literature review may cover some historical background with more focus on recent research, or it may cover recent and historical findings equally.

Use a range of resources including books, journal articles, websites, theses, conference papers, government document and reports to compile information on your topic.

Find books in Omni .

An easy way to find a book is to ask someone knowledgeable on your subject - librarians, professors, advisors, etc.

If the library does not have a specific book borrow from another the library . Search for books on Worldcat and request them through Interlibrary Loan .

To get started, look up your topic in an encyclopedia and check the references at the end of the entry.

Look through the bibliography of key books for hints about leading theories, resources, and researchers in the field.

Search for theses in the Theses Canada Portal , Proquest Dissertations and Theses (PQDT) and e-scholar@Ontario Tech . Thesis papers always have a literature review section.

Search for articles on your subject.

Read through the literature review section of articles on your topic. Most articles contain a literature review section after the introduction.

Look for book reviews on your subject in the databases. Use Book Reviews to determine if a book covers your subject adequately and is worth reading.

Look through the bibliography of key articles for hints about leading theories, resources, and researchers in the field.

Request articles the library does not have through Interlibrary Loan .

Find out how many times an article has been cited by others to identify the most influential articles. Find highest impact journals using Journal Citation Reports.

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How To Write An A-Grade Literature Review

3 straightforward steps (with examples) + free template.

By: Derek Jansen (MBA) | Expert Reviewed By: Dr. Eunice Rautenbach | October 2019

Quality research is about building onto the existing work of others , “standing on the shoulders of giants”, as Newton put it. The literature review chapter of your dissertation, thesis or research project is where you synthesise this prior work and lay the theoretical foundation for your own research.

Long story short, this chapter is a pretty big deal, which is why you want to make sure you get it right . In this post, I’ll show you exactly how to write a literature review in three straightforward steps, so you can conquer this vital chapter (the smart way).

Overview: The Literature Review Process

• Understanding the “ why “
• Finding the relevant literature
• Cataloguing and synthesising the information
• Outlining & writing up your literature review
• Example of a literature review

But first, the “why”…

Before we unpack how to write the literature review chapter, we’ve got to look at the why . To put it bluntly, if you don’t understand the function and purpose of the literature review process, there’s no way you can pull it off well. So, what exactly is the purpose of the literature review?

Well, there are (at least) four core functions:

• For you to gain an understanding (and demonstrate this understanding) of where the research is at currently, what the key arguments and disagreements are.
• For you to identify the gap(s) in the literature and then use this as justification for your own research topic.
• To help you build a conceptual framework for empirical testing (if applicable to your research topic).
• To inform your methodological choices and help you source tried and tested questionnaires (for interviews ) and measurement instruments (for surveys ).

Most students understand the first point but don’t give any thought to the rest. To get the most from the literature review process, you must keep all four points front of mind as you review the literature (more on this shortly), or you’ll land up with a wonky foundation.

Okay – with the why out the way, let’s move on to the how . As mentioned above, writing your literature review is a process, which I’ll break down into three steps:

• Finding the most suitable literature
• Understanding , distilling and organising the literature
• Planning and writing up your literature review chapter

Importantly, you must complete steps one and two before you start writing up your chapter. I know it’s very tempting, but don’t try to kill two birds with one stone and write as you read. You’ll invariably end up wasting huge amounts of time re-writing and re-shaping, or you’ll just land up with a disjointed, hard-to-digest mess . Instead, you need to read first and distil the information, then plan and execute the writing.

Step 1: Find the relevant literature

Naturally, the first step in the literature review journey is to hunt down the existing research that’s relevant to your topic. While you probably already have a decent base of this from your research proposal , you need to expand on this substantially in the dissertation or thesis itself.

Essentially, you need to be looking for any existing literature that potentially helps you answer your research question (or develop it, if that’s not yet pinned down). There are numerous ways to find relevant literature, but I’ll cover my top four tactics here. I’d suggest combining all four methods to ensure that nothing slips past you:

Method 1 – Google Scholar Scrubbing

Google’s academic search engine, Google Scholar , is a great starting point as it provides a good high-level view of the relevant journal articles for whatever keyword you throw at it. Most valuably, it tells you how many times each article has been cited, which gives you an idea of how credible (or at least, popular) it is. Some articles will be free to access, while others will require an account, which brings us to the next method.

Method 2 – University Database Scrounging

Generally, universities provide students with access to an online library, which provides access to many (but not all) of the major journals.

So, if you find an article using Google Scholar that requires paid access (which is quite likely), search for that article in your university’s database – if it’s listed there, you’ll have access. Note that, generally, the search engine capabilities of these databases are poor, so make sure you search for the exact article name, or you might not find it.

Method 3 – Journal Article Snowballing

At the end of every academic journal article, you’ll find a list of references. As with any academic writing, these references are the building blocks of the article, so if the article is relevant to your topic, there’s a good chance a portion of the referenced works will be too. Do a quick scan of the titles and see what seems relevant, then search for the relevant ones in your university’s database.

Method 4 – Dissertation Scavenging

Similar to Method 3 above, you can leverage other students’ dissertations. All you have to do is skim through literature review chapters of existing dissertations related to your topic and you’ll find a gold mine of potential literature. Usually, your university will provide you with access to previous students’ dissertations, but you can also find a much larger selection in the following databases:

• Open Access Theses & Dissertations
• Stanford SearchWorks

Keep in mind that dissertations and theses are not as academically sound as published, peer-reviewed journal articles (because they’re written by students, not professionals), so be sure to check the credibility of any sources you find using this method. You can do this by assessing the citation count of any given article in Google Scholar. If you need help with assessing the credibility of any article, or with finding relevant research in general, you can chat with one of our Research Specialists .

Alright – with a good base of literature firmly under your belt, it’s time to move onto the next step.

Need a helping hand?

Step 2: Log, catalogue and synthesise

Once you’ve built a little treasure trove of articles, it’s time to get reading and start digesting the information – what does it all mean?

While I present steps one and two (hunting and digesting) as sequential, in reality, it’s more of a back-and-forth tango – you’ll read a little , then have an idea, spot a new citation, or a new potential variable, and then go back to searching for articles. This is perfectly natural – through the reading process, your thoughts will develop , new avenues might crop up, and directional adjustments might arise. This is, after all, one of the main purposes of the literature review process (i.e. to familiarise yourself with the current state of research in your field).

As you’re working through your treasure chest, it’s essential that you simultaneously start organising the information. There are three aspects to this:

• Logging reference information
• Building an organised catalogue
• Distilling and synthesising the information

I’ll discuss each of these below:

2.1 – Log the reference information

As you read each article, you should add it to your reference management software. I usually recommend Mendeley for this purpose (see the Mendeley 101 video below), but you can use whichever software you’re comfortable with. Most importantly, make sure you load EVERY article you read into your reference manager, even if it doesn’t seem very relevant at the time.

2.2 – Build an organised catalogue

In the beginning, you might feel confident that you can remember who said what, where, and what their main arguments were. Trust me, you won’t. If you do a thorough review of the relevant literature (as you must!), you’re going to read many, many articles, and it’s simply impossible to remember who said what, when, and in what context . Also, without the bird’s eye view that a catalogue provides, you’ll miss connections between various articles, and have no view of how the research developed over time. Simply put, it’s essential to build your own catalogue of the literature.

I would suggest using Excel to build your catalogue, as it allows you to run filters, colour code and sort – all very useful when your list grows large (which it will). How you lay your spreadsheet out is up to you, but I’d suggest you have the following columns (at minimum):

• Author, date, title – Start with three columns containing this core information. This will make it easy for you to search for titles with certain words, order research by date, or group by author.
• Categories or keywords – You can either create multiple columns, one for each category/theme and then tick the relevant categories, or you can have one column with keywords.
• Key arguments/points – Use this column to succinctly convey the essence of the article, the key arguments and implications thereof for your research.
• Context – Note the socioeconomic context in which the research was undertaken. For example, US-based, respondents aged 25-35, lower- income, etc. This will be useful for making an argument about gaps in the research.
• Methodology – Note which methodology was used and why. Also, note any issues you feel arise due to the methodology. Again, you can use this to make an argument about gaps in the research.
• Quotations – Note down any quoteworthy lines you feel might be useful later.
• Notes – Make notes about anything not already covered. For example, linkages to or disagreements with other theories, questions raised but unanswered, shortcomings or limitations, and so forth.

If you’d like, you can try out our free catalog template here (see screenshot below).

2.3 – Digest and synthesise

Most importantly, as you work through the literature and build your catalogue, you need to synthesise all the information in your own mind – how does it all fit together? Look for links between the various articles and try to develop a bigger picture view of the state of the research. Some important questions to ask yourself are:

• What answers does the existing research provide to my own research questions ?
• Which points do the researchers agree (and disagree) on?
• How has the research developed over time?
• Where do the gaps in the current research lie?

To help you develop a big-picture view and synthesise all the information, you might find mind mapping software such as Freemind useful. Alternatively, if you’re a fan of physical note-taking, investing in a large whiteboard might work for you.

Step 3: Outline and write it up!

Once you’re satisfied that you have digested and distilled all the relevant literature in your mind, it’s time to put pen to paper (or rather, fingers to keyboard). There are two steps here – outlining and writing:

3.1 – Draw up your outline

Having spent so much time reading, it might be tempting to just start writing up without a clear structure in mind. However, it’s critically important to decide on your structure and develop a detailed outline before you write anything. Your literature review chapter needs to present a clear, logical and an easy to follow narrative – and that requires some planning. Don’t try to wing it!

Naturally, you won’t always follow the plan to the letter, but without a detailed outline, you’re more than likely going to end up with a disjointed pile of waffle , and then you’re going to spend a far greater amount of time re-writing, hacking and patching. The adage, “measure twice, cut once” is very suitable here.

In terms of structure, the first decision you’ll have to make is whether you’ll lay out your review thematically (into themes) or chronologically (by date/period). The right choice depends on your topic, research objectives and research questions, which we discuss in this article .

Once that’s decided, you need to draw up an outline of your entire chapter in bullet point format. Try to get as detailed as possible, so that you know exactly what you’ll cover where, how each section will connect to the next, and how your entire argument will develop throughout the chapter. Also, at this stage, it’s a good idea to allocate rough word count limits for each section, so that you can identify word count problems before you’ve spent weeks or months writing!

PS – check out our free literature review chapter template…

3.2 – Get writing

With a detailed outline at your side, it’s time to start writing up (finally!). At this stage, it’s common to feel a bit of writer’s block and find yourself procrastinating under the pressure of finally having to put something on paper. To help with this, remember that the objective of the first draft is not perfection – it’s simply to get your thoughts out of your head and onto paper, after which you can refine them. The structure might change a little, the word count allocations might shift and shuffle, and you might add or remove a section – that’s all okay. Don’t worry about all this on your first draft – just get your thoughts down on paper.

Once you’ve got a full first draft (however rough it may be), step away from it for a day or two (longer if you can) and then come back at it with fresh eyes. Pay particular attention to the flow and narrative – does it fall fit together and flow from one section to another smoothly? Now’s the time to try to improve the linkage from each section to the next, tighten up the writing to be more concise, trim down word count and sand it down into a more digestible read.

Once you’ve done that, give your writing to a friend or colleague who is not a subject matter expert and ask them if they understand the overall discussion. The best way to assess this is to ask them to explain the chapter back to you. This technique will give you a strong indication of which points were clearly communicated and which weren’t. If you’re working with Grad Coach, this is a good time to have your Research Specialist review your chapter.

Finally, tighten it up and send it off to your supervisor for comment. Some might argue that you should be sending your work to your supervisor sooner than this (indeed your university might formally require this), but in my experience, supervisors are extremely short on time (and often patience), so, the more refined your chapter is, the less time they’ll waste on addressing basic issues (which you know about already) and the more time they’ll spend on valuable feedback that will increase your mark-earning potential.

Literature Review Example

In the video below, we unpack an actual literature review so that you can see how all the core components come together in reality.

Let’s Recap

In this post, we’ve covered how to research and write up a high-quality literature review chapter. Let’s do a quick recap of the key takeaways:

• It is essential to understand the WHY of the literature review before you read or write anything. Make sure you understand the 4 core functions of the process.
• The first step is to hunt down the relevant literature . You can do this using Google Scholar, your university database, the snowballing technique and by reviewing other dissertations and theses.
• Next, you need to log all the articles in your reference manager , build your own catalogue of literature and synthesise all the research.
• Following that, you need to develop a detailed outline of your entire chapter – the more detail the better. Don’t start writing without a clear outline (on paper, not in your head!)
• Write up your first draft in rough form – don’t aim for perfection. Remember, done beats perfect.
• Refine your second draft and get a layman’s perspective on it . Then tighten it up and submit it to your supervisor.

Psst… there’s more!

This post is an extract from our bestselling short course, Literature Review Bootcamp . If you want to work smart, you don't want to miss this .

38 Comments

Thank you very much. This page is an eye opener and easy to comprehend.

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I wish I come across GradCoach earlier enough.

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Thank you for this good job.

Keep it up!

You’re welcome, Yinka. Thank you for the kind words. All the best writing your literature review.

Thank you for a very useful literature review session. Although I am doing most of the steps…it being my first masters an Mphil is a self study and one not sure you are on the right track. I have an amazing supervisor but one also knows they are super busy. So not wanting to bother on the minutae. Thank you.

You’re most welcome, Renee. Good luck with your literature review 🙂

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You’re welcome, Maithe. Good luck writing your literature review 🙂

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Great piece, so enriching and it is going to help me a great lot in my project and thesis, thanks so much

This is THE BEST site for ANYONE doing a masters or doctorate! Thank you for the sound advice and templates. You rock!

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I am doing two papers on my final year thesis, and I must stay I feel very confident to face both headlong after reading this article.

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if anyone is to get a paper done on time and in the best way possible, GRADCOACH is certainly the go to area!

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Good morning scholar. I’m delighted coming to know you even before the commencement of my dissertation which hopefully is expected in not more than six months from now. I would love to engage my study under your guidance from the beginning to the end. I love to know how to do good job

Thank you so much Derek for such useful information on writing up a good literature review. I am at a stage where I need to start writing my one. My proposal was accepted late last year but I honestly did not know where to start

Like the name of your YouTube implies you are GRAD (great,resource person, about dissertation). In short you are smart enough in coaching research work.

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I appreciate.

Very comprehensive and eye opener for me as beginner in postgraduate study. Well explained and easy to understand. Appreciate and good reference in guiding me in my research journey. Thank you

Thank you. I requested to download the free literature review template, however, your website wouldn’t allow me to complete the request or complete a download. May I request that you email me the free template? Thank you.

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Harvey Cushing/John Hay Whitney Medical Library

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YSN Doctoral Programs: Steps in Conducting a Literature Review

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• Steps in Conducting a Literature Review

What is a literature review?

A literature review is an integrated analysis -- not just a summary-- of scholarly writings and other relevant evidence related directly to your research question.  That is, it represents a synthesis of the evidence that provides background information on your topic and shows a association between the evidence and your research question.

A literature review may be a stand alone work or the introduction to a larger research paper, depending on the assignment.  Rely heavily on the guidelines your instructor has given you.

Why is it important?

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Discovers relationships between research studies/ideas.
• Identifies major themes, concepts, and researchers on a topic.
• Identifies critical gaps and points of disagreement.
• Discusses further research questions that logically come out of the previous studies.

APA7 Style resources

APA Style Blog - for those harder to find answers

1. Choose a topic. Define your research question.

Your literature review should be guided by your central research question.  The literature represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.

• Make sure your research question is not too broad or too narrow.  Is it manageable?
• Begin writing down terms that are related to your question. These will be useful for searches later.
• If you have the opportunity, discuss your topic with your professor and your class mates.

2. Decide on the scope of your review

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

• This may depend on your assignment.  How many sources does the assignment require?

3. Select the databases you will use to conduct your searches.

Make a list of the databases you will search. 

Where to find databases:

• use the tabs on this guide
• Find other databases in the Nursing Information Resources web page
• More on the Medical Library web page
• ... and more on the Yale University Library web page

4. Conduct your searches to find the evidence. Keep track of your searches.

• Use the key words in your question, as well as synonyms for those words, as terms in your search. Use the database tutorials for help.
• Save the searches in the databases. This saves time when you want to redo, or modify, the searches. It is also helpful to use as a guide is the searches are not finding any useful results.
• Review the abstracts of research studies carefully. This will save you time.
• Use the bibliographies and references of research studies you find to locate others.
• Check with your professor, or a subject expert in the field, if you are missing any key works in the field.
• Ask your librarian for help at any time.
• Use a citation manager, such as EndNote as the repository for your citations. See the EndNote tutorials for help.

Review the literature

Some questions to help you analyze the research:

• What was the research question of the study you are reviewing? What were the authors trying to discover?
• Was the research funded by a source that could influence the findings?
• What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions.
• Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
• If there are conflicting studies, why do you think that is?
• How are the authors viewed in the field? Has this study been cited? If so, how has it been analyzed?

Tips: 

• Review the abstracts carefully.  
• Keep careful notes so that you may track your thought processes during the research process.
• Create a matrix of the studies for easy analysis, and synthesis, across all of the studies.
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Literature reviews

• Introduction
• Conduct your search
• Store and organise the literature
• Evaluate and critique the literature
• Different subject areas

Find literature reviews on your topic

Find reviews

• Run your search in the database
• Limit the results to review or literature review -  often found under Document type

If there is no option to limit to reviews try adding the word "review" to your search.

• Go to the Advanced search of the database

• Type  review  into a search line and change the field option to Title

Note: The results may include book reviews using this method.

Useful databases to find review articles

• Annual reviews online Annual Reviews publishes analytic reviews in focused disciplines within the biomedical, physical, and social sciences. The reviews cover significant developments in the different fields.
• Web of Science Go to the Advanced Search to set the document type to "Review". Web of Science covers the sciences, social sciences, arts and humanities.
• Scopus Click on Limit to change the Document type to Review. Scopus is a multidisciplinary abstract and citation database of peer reviewed literature, book reviews and conference proceedings.
• Subject guides These guides list recommended databases useful for your particular subject area.
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• URL: https://guides.library.uq.edu.au/research-techniques/literature-reviews

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The Literature Review

Primary and secondary sources, the literature review: primary and secondary sources.

• Searching the literature
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• The Literature Review Toolbox

On this page

• Primary vs secondary sources: The differences explained 

Can something be both a primary and secondary source?

Research for your literature review can be categorised as either primary or secondary in nature. The simplest definition of primary sources is either original information (such as survey data) or a first person account of an event (such as an interview transcript). Whereas secondary sources are any publshed or unpublished works that describe, summarise, analyse, evaluate, interpret or review primary source materials. Secondary sources can incorporate primary sources to support their arguments.

Ideally, good research should use a combination of both primary and secondary sources. For example, if a researcher were to investigate the introduction of a law and the impacts it had on a community, he/she might look at the transcripts of the parliamentary debates as well as the parliamentary commentary and news reporting surrounding the laws at the time. 

Examples of primary and secondary sources

Primary vs secondary sources: The differences explained

Finding primary sources

• VU Special Collections  - The Special Collections at Victoria University Library are a valuable research resource. The Collections have strong threads of radical literature, particularly Australian Communist literature, much of which is rare or unique. Women and urban planning also feature across the Collections. There are collections that give you a picture of the people who donated them like Ray Verrills, John McLaren, Sir Zelman Cowen, and Ruth & Maurie Crow. Other collections focus on Australia's neighbours – PNG and Timor-Leste.
• POLICY - Sharing the latest in policy knowledge and evidence, this database supports enhanced learning, collaboration and contribution.
• Indigenous Australia  -  The Indigenous Australia database represents the collections of the Aboriginal and Torres Strait Islander Commission Library.
• Australian Heritage Bibliography - Aboriginal and Torres Strait Islander Subset (AHB-ATSIS)  - AHB is a bibliographic database that indexes and abstracts articles from published and unpublished material on Australia's natural and cultural environment. The AHB-ATSIS subset contains records that specifically relate to the Aboriginal and Torres Strait Islander peoples.include journal articles, unpublished reports, books, videos and conference proceedings from many different sources around Australia. Emphasis is placed on reports written or commissioned by government and non-government heritage agencies throughout the country.
• ATSIhealth  - The Aboriginal and Torres Strait Islander Health Bibliography (ATSIhealth), compiled by Neil Thomson and Natalie Weissofner at the School of Indigenous Australian Studies, Kurongkurl Katitjin, Edith Cowan University, is a bibliographic database that indexes published and unpublished material on Australian Indigenous health. Source documents include theses, unpublished articles, government reports, conference papers, abstracts, book chapters, books, discussion and working papers, and statistical documents. 
• National Archive of Australia  - The National Archives of Australia holds the memory of our nation and keeps vital Australian Government records safe. 
• National Library of Australia: Manuscripts  - Manuscripts collection that is wide ranging and provides rich evidence of the lives and activities of Australians who have shaped our society.
• National Library of Australia: Printed ephemera  - The National Library has been selectively collecting Australian printed ephemera since the early 1960s as a record of Australian life and social customs, popular culture, national events, and issues of national concern.
• National Library of Australia: Oral history and folklore - The Library’s Oral History and Folklore Collection dates back to the 1950’s and includes a rich and diverse collection of interviews and recordings with Australians from all walks of life.
• Historic Hansard - Commonwealth of Australia parliamentary debates presented in an easy-to-read format for historians and other lovers of political speech.
• The Old Bailey Online - A fully searchable edition of the largest body of texts detailing the lives of non-elite people ever published, containing 197,745 criminal trials held at London's central criminal court.

Whether or not a source can be considered both primary and  secondary, depends on the context. In some instances, material may act as a secondary source for one research area, and as a primary source for another. For example, Niccolò Machiavelli’s The Prince , published in 1513, is an important secondary source for any study of the various Renaissance princes in the Medici family; but the same book is also a primary source for the political thought that was characteristic of the sixteenth century because it reflects the attitudes of a person living in the 1500s.

Source: Craver, 1999, as cited in University of South Australia Library. (2021, Oct 6).  Can something be a primary and secondary source?.  University of South Australia Library. https://guides.library.unisa.edu.au/historycultural/sourcetypes

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• v.7(1); 2018 Feb

Writing an effective literature review

Lorelei lingard.

Schulich School of Medicine & Dentistry, Health Sciences Addition, Western University, London, Ontario Canada

In the Writer’s Craft section we offer simple tips to improve your writing in one of three areas: Energy, Clarity and Persuasiveness. Each entry focuses on a key writing feature or strategy, illustrates how it commonly goes wrong, teaches the grammatical underpinnings necessary to understand it and offers suggestions to wield it effectively. We encourage readers to share comments on or suggestions for this section on Twitter, using the hashtag: #how’syourwriting?

This Writer’s Craft instalment is the first in a two-part series that offers strategies for effectively presenting the literature review section of a research manuscript. This piece alerts writers to the importance of not only summarizing what is known but also identifying precisely what is not, in order to explicitly signal the relevance of their research. In this instalment, I will introduce readers to the mapping the gap metaphor, the knowledge claims heuristic, and the need to characterize the gap.

Mapping the gap

The purpose of the literature review section of a manuscript is not to report what is known about your topic. The purpose is to identify what remains unknown— what academic writing scholar Janet Giltrow has called the ‘knowledge deficit’ — thus establishing the need for your research study [ 1 ]. In an earlier Writer’s Craft instalment, the Problem-Gap-Hook heuristic was introduced as a way of opening your paper with a clear statement of the problem that your work grapples with, the gap in our current knowledge about that problem, and the reason the gap matters [ 2 ]. This article explains how to use the literature review section of your paper to build and characterize the Gap claim in your Problem-Gap-Hook. The metaphor of ‘mapping the gap’ is a way of thinking about how to select and arrange your review of the existing literature so that readers can recognize why your research needed to be done, and why its results constitute a meaningful advance on what was already known about the topic.

Many writers have learned that the literature review should describe what is known. The trouble with this approach is that it can produce a laundry list of facts-in-the-world that does not persuade the reader that the current study is a necessary next step. Instead, think of your literature review as painting in a map of your research domain: as you review existing knowledge, you are painting in sections of the map, but your goal is not to end with the whole map fully painted. That would mean there is nothing more we need to know about the topic, and that leaves no room for your research. What you want to end up with is a map in which painted sections surround and emphasize a white space, a gap in what is known that matters. Conceptualizing your literature review this way helps to ensure that it achieves its dual goal: of presenting what is known and pointing out what is not—the latter of these goals is necessary for your literature review to establish the necessity and importance of the research you are about to describe in the methods section which will immediately follow the literature review.

To a novice researcher or graduate student, this may seem counterintuitive. Hopefully you have invested significant time in reading the existing literature, and you are understandably keen to demonstrate that you’ve read everything ever published about your topic! Be careful, though, not to use the literature review section to regurgitate all of your reading in manuscript form. For one thing, it creates a laundry list of facts that makes for horrible reading. But there are three other reasons for avoiding this approach. First, you don’t have the space. In published medical education research papers, the literature review is quite short, ranging from a few paragraphs to a few pages, so you can’t summarize everything you’ve read. Second, you’re preaching to the converted. If you approach your paper as a contribution to an ongoing scholarly conversation,[ 2 ] then your literature review should summarize just the aspects of that conversation that are required to situate your conversational turn as informed and relevant. Third, the key to relevance is to point to a gap in what is known. To do so, you summarize what is known for the express purpose of identifying what is not known . Seen this way, the literature review should exert a gravitational pull on the reader, leading them inexorably to the white space on the map of knowledge you’ve painted for them. That white space is the space that your research fills.

Knowledge claims

To help writers move beyond the laundry list, the notion of ‘knowledge claims’ can be useful. A knowledge claim is a way of presenting the growing understanding of the community of researchers who have been exploring your topic. These are not disembodied facts, but rather incremental insights that some in the field may agree with and some may not, depending on their different methodological and disciplinary approaches to the topic. Treating the literature review as a story of the knowledge claims being made by researchers in the field can help writers with one of the most sophisticated aspects of a literature review—locating the knowledge being reviewed. Where does it come from? What is debated? How do different methodologies influence the knowledge being accumulated? And so on.

Consider this example of the knowledge claims (KC), Gap and Hook for the literature review section of a research paper on distributed healthcare teamwork:

KC: We know that poor team communication can cause errors. KC: And we know that team training can be effective in improving team communication. KC: This knowledge has prompted a push to incorporate teamwork training principles into health professions education curricula. KC: However, most of what we know about team training research has come from research with co-located teams—i. e., teams whose members work together in time and space. Gap: Little is known about how teamwork training principles would apply in distributed teams, whose members work asynchronously and are spread across different locations. Hook: Given that much healthcare teamwork is distributed rather than co-located, our curricula will be severely lacking until we create refined teamwork training principles that reflect distributed as well as co-located work contexts.

The ‘We know that …’ structure illustrated in this example is a template for helping you draft and organize. In your final version, your knowledge claims will be expressed with more sophistication. For instance, ‘We know that poor team communication can cause errors’ will become something like ‘Over a decade of patient safety research has demonstrated that poor team communication is the dominant cause of medical errors.’ This simple template of knowledge claims, though, provides an outline for the paragraphs in your literature review, each of which will provide detailed evidence to illustrate a knowledge claim. Using this approach, the order of the paragraphs in the literature review is strategic and persuasive, leading the reader to the gap claim that positions the relevance of the current study. To expand your vocabulary for creating such knowledge claims, linking them logically and positioning yourself amid them, I highly recommend Graff and Birkenstein’s little handbook of ‘templates’ [ 3 ].

As you organize your knowledge claims, you will also want to consider whether you are trying to map the gap in a well-studied field, or a relatively understudied one. The rhetorical challenge is different in each case. In a well-studied field, like professionalism in medical education, you must make a strong, explicit case for the existence of a gap. Readers may come to your paper tired of hearing about this topic and tempted to think we can’t possibly need more knowledge about it. Listing the knowledge claims can help you organize them most effectively and determine which pieces of knowledge may be unnecessary to map the white space your research attempts to fill. This does not mean that you leave out relevant information: your literature review must still be accurate. But, since you will not be able to include everything, selecting carefully among the possible knowledge claims is essential to producing a coherent, well-argued literature review.

Characterizing the gap

Once you’ve identified the gap, your literature review must characterize it. What kind of gap have you found? There are many ways to characterize a gap, but some of the more common include:

• a pure knowledge deficit—‘no one has looked at the relationship between longitudinal integrated clerkships and medical student abuse’
• a shortcoming in the scholarship, often due to philosophical or methodological tendencies and oversights—‘scholars have interpreted x from a cognitivist perspective, but ignored the humanist perspective’ or ‘to date, we have surveyed the frequency of medical errors committed by residents, but we have not explored their subjective experience of such errors’
• a controversy—‘scholars disagree on the definition of professionalism in medicine …’
• a pervasive and unproven assumption—‘the theme of technological heroism—technology will solve what ails teamwork—is ubiquitous in the literature, but what is that belief based on?’

To characterize the kind of gap, you need to know the literature thoroughly. That means more than understanding each paper individually; you also need to be placing each paper in relation to others. This may require changing your note-taking technique while you’re reading; take notes on what each paper contributes to knowledge, but also on how it relates to other papers you’ve read, and what it suggests about the kind of gap that is emerging.

In summary, think of your literature review as mapping the gap rather than simply summarizing the known. And pay attention to characterizing the kind of gap you’ve mapped. This strategy can help to make your literature review into a compelling argument rather than a list of facts. It can remind you of the danger of describing so fully what is known that the reader is left with the sense that there is no pressing need to know more. And it can help you to establish a coherence between the kind of gap you’ve identified and the study methodology you will use to fill it.

Acknowledgements

Thanks to Mark Goldszmidt for his feedback on an early version of this manuscript.

PhD, is director of the Centre for Education Research & Innovation at Schulich School of Medicine & Dentistry, and professor for the Department of Medicine at Western University in London, Ontario, Canada.