is a literature review written in past or present tense

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• v.9(7); 2013 Jul

Ten Simple Rules for Writing a Literature Review

Marco pautasso.

1 Centre for Functional and Evolutionary Ecology (CEFE), CNRS, Montpellier, France

2 Centre for Biodiversity Synthesis and Analysis (CESAB), FRB, Aix-en-Provence, France

Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications [1] . For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively [2] . Given such mountains of papers, scientists cannot be expected to examine in detail every single new paper relevant to their interests [3] . Thus, it is both advantageous and necessary to rely on regular summaries of the recent literature. Although recognition for scientists mainly comes from primary research, timely literature reviews can lead to new synthetic insights and are often widely read [4] . For such summaries to be useful, however, they need to be compiled in a professional way [5] .

When starting from scratch, reviewing the literature can require a titanic amount of work. That is why researchers who have spent their career working on a certain research issue are in a perfect position to review that literature. Some graduate schools are now offering courses in reviewing the literature, given that most research students start their project by producing an overview of what has already been done on their research issue [6] . However, it is likely that most scientists have not thought in detail about how to approach and carry out a literature review.

Reviewing the literature requires the ability to juggle multiple tasks, from finding and evaluating relevant material to synthesising information from various sources, from critical thinking to paraphrasing, evaluating, and citation skills [7] . In this contribution, I share ten simple rules I learned working on about 25 literature reviews as a PhD and postdoctoral student. Ideas and insights also come from discussions with coauthors and colleagues, as well as feedback from reviewers and editors.

Rule 1: Define a Topic and Audience

How to choose which topic to review? There are so many issues in contemporary science that you could spend a lifetime of attending conferences and reading the literature just pondering what to review. On the one hand, if you take several years to choose, several other people may have had the same idea in the meantime. On the other hand, only a well-considered topic is likely to lead to a brilliant literature review [8] . The topic must at least be:

• interesting to you (ideally, you should have come across a series of recent papers related to your line of work that call for a critical summary),
• an important aspect of the field (so that many readers will be interested in the review and there will be enough material to write it), and
• a well-defined issue (otherwise you could potentially include thousands of publications, which would make the review unhelpful).

Ideas for potential reviews may come from papers providing lists of key research questions to be answered [9] , but also from serendipitous moments during desultory reading and discussions. In addition to choosing your topic, you should also select a target audience. In many cases, the topic (e.g., web services in computational biology) will automatically define an audience (e.g., computational biologists), but that same topic may also be of interest to neighbouring fields (e.g., computer science, biology, etc.).

Rule 2: Search and Re-search the Literature

After having chosen your topic and audience, start by checking the literature and downloading relevant papers. Five pieces of advice here:

• keep track of the search items you use (so that your search can be replicated [10] ),
• keep a list of papers whose pdfs you cannot access immediately (so as to retrieve them later with alternative strategies),
• use a paper management system (e.g., Mendeley, Papers, Qiqqa, Sente),
• define early in the process some criteria for exclusion of irrelevant papers (these criteria can then be described in the review to help define its scope), and
• do not just look for research papers in the area you wish to review, but also seek previous reviews.

The chances are high that someone will already have published a literature review ( Figure 1 ), if not exactly on the issue you are planning to tackle, at least on a related topic. If there are already a few or several reviews of the literature on your issue, my advice is not to give up, but to carry on with your own literature review,

The bottom-right situation (many literature reviews but few research papers) is not just a theoretical situation; it applies, for example, to the study of the impacts of climate change on plant diseases, where there appear to be more literature reviews than research studies [33] .

• discussing in your review the approaches, limitations, and conclusions of past reviews,
• trying to find a new angle that has not been covered adequately in the previous reviews, and
• incorporating new material that has inevitably accumulated since their appearance.

When searching the literature for pertinent papers and reviews, the usual rules apply:

• be thorough,
• use different keywords and database sources (e.g., DBLP, Google Scholar, ISI Proceedings, JSTOR Search, Medline, Scopus, Web of Science), and
• look at who has cited past relevant papers and book chapters.

Rule 3: Take Notes While Reading

If you read the papers first, and only afterwards start writing the review, you will need a very good memory to remember who wrote what, and what your impressions and associations were while reading each single paper. My advice is, while reading, to start writing down interesting pieces of information, insights about how to organize the review, and thoughts on what to write. This way, by the time you have read the literature you selected, you will already have a rough draft of the review.

Of course, this draft will still need much rewriting, restructuring, and rethinking to obtain a text with a coherent argument [11] , but you will have avoided the danger posed by staring at a blank document. Be careful when taking notes to use quotation marks if you are provisionally copying verbatim from the literature. It is advisable then to reformulate such quotes with your own words in the final draft. It is important to be careful in noting the references already at this stage, so as to avoid misattributions. Using referencing software from the very beginning of your endeavour will save you time.

Rule 4: Choose the Type of Review You Wish to Write

After having taken notes while reading the literature, you will have a rough idea of the amount of material available for the review. This is probably a good time to decide whether to go for a mini- or a full review. Some journals are now favouring the publication of rather short reviews focusing on the last few years, with a limit on the number of words and citations. A mini-review is not necessarily a minor review: it may well attract more attention from busy readers, although it will inevitably simplify some issues and leave out some relevant material due to space limitations. A full review will have the advantage of more freedom to cover in detail the complexities of a particular scientific development, but may then be left in the pile of the very important papers “to be read” by readers with little time to spare for major monographs.

There is probably a continuum between mini- and full reviews. The same point applies to the dichotomy of descriptive vs. integrative reviews. While descriptive reviews focus on the methodology, findings, and interpretation of each reviewed study, integrative reviews attempt to find common ideas and concepts from the reviewed material [12] . A similar distinction exists between narrative and systematic reviews: while narrative reviews are qualitative, systematic reviews attempt to test a hypothesis based on the published evidence, which is gathered using a predefined protocol to reduce bias [13] , [14] . When systematic reviews analyse quantitative results in a quantitative way, they become meta-analyses. The choice between different review types will have to be made on a case-by-case basis, depending not just on the nature of the material found and the preferences of the target journal(s), but also on the time available to write the review and the number of coauthors [15] .

Rule 5: Keep the Review Focused, but Make It of Broad Interest

Whether your plan is to write a mini- or a full review, it is good advice to keep it focused 16 , 17 . Including material just for the sake of it can easily lead to reviews that are trying to do too many things at once. The need to keep a review focused can be problematic for interdisciplinary reviews, where the aim is to bridge the gap between fields [18] . If you are writing a review on, for example, how epidemiological approaches are used in modelling the spread of ideas, you may be inclined to include material from both parent fields, epidemiology and the study of cultural diffusion. This may be necessary to some extent, but in this case a focused review would only deal in detail with those studies at the interface between epidemiology and the spread of ideas.

While focus is an important feature of a successful review, this requirement has to be balanced with the need to make the review relevant to a broad audience. This square may be circled by discussing the wider implications of the reviewed topic for other disciplines.

Rule 6: Be Critical and Consistent

Reviewing the literature is not stamp collecting. A good review does not just summarize the literature, but discusses it critically, identifies methodological problems, and points out research gaps [19] . After having read a review of the literature, a reader should have a rough idea of:

• the major achievements in the reviewed field,
• the main areas of debate, and
• the outstanding research questions.

It is challenging to achieve a successful review on all these fronts. A solution can be to involve a set of complementary coauthors: some people are excellent at mapping what has been achieved, some others are very good at identifying dark clouds on the horizon, and some have instead a knack at predicting where solutions are going to come from. If your journal club has exactly this sort of team, then you should definitely write a review of the literature! In addition to critical thinking, a literature review needs consistency, for example in the choice of passive vs. active voice and present vs. past tense.

Rule 7: Find a Logical Structure

Like a well-baked cake, a good review has a number of telling features: it is worth the reader's time, timely, systematic, well written, focused, and critical. It also needs a good structure. With reviews, the usual subdivision of research papers into introduction, methods, results, and discussion does not work or is rarely used. However, a general introduction of the context and, toward the end, a recapitulation of the main points covered and take-home messages make sense also in the case of reviews. For systematic reviews, there is a trend towards including information about how the literature was searched (database, keywords, time limits) [20] .

How can you organize the flow of the main body of the review so that the reader will be drawn into and guided through it? It is generally helpful to draw a conceptual scheme of the review, e.g., with mind-mapping techniques. Such diagrams can help recognize a logical way to order and link the various sections of a review [21] . This is the case not just at the writing stage, but also for readers if the diagram is included in the review as a figure. A careful selection of diagrams and figures relevant to the reviewed topic can be very helpful to structure the text too [22] .

Rule 8: Make Use of Feedback

Reviews of the literature are normally peer-reviewed in the same way as research papers, and rightly so [23] . As a rule, incorporating feedback from reviewers greatly helps improve a review draft. Having read the review with a fresh mind, reviewers may spot inaccuracies, inconsistencies, and ambiguities that had not been noticed by the writers due to rereading the typescript too many times. It is however advisable to reread the draft one more time before submission, as a last-minute correction of typos, leaps, and muddled sentences may enable the reviewers to focus on providing advice on the content rather than the form.

Feedback is vital to writing a good review, and should be sought from a variety of colleagues, so as to obtain a diversity of views on the draft. This may lead in some cases to conflicting views on the merits of the paper, and on how to improve it, but such a situation is better than the absence of feedback. A diversity of feedback perspectives on a literature review can help identify where the consensus view stands in the landscape of the current scientific understanding of an issue [24] .

Rule 9: Include Your Own Relevant Research, but Be Objective

In many cases, reviewers of the literature will have published studies relevant to the review they are writing. This could create a conflict of interest: how can reviewers report objectively on their own work [25] ? Some scientists may be overly enthusiastic about what they have published, and thus risk giving too much importance to their own findings in the review. However, bias could also occur in the other direction: some scientists may be unduly dismissive of their own achievements, so that they will tend to downplay their contribution (if any) to a field when reviewing it.

In general, a review of the literature should neither be a public relations brochure nor an exercise in competitive self-denial. If a reviewer is up to the job of producing a well-organized and methodical review, which flows well and provides a service to the readership, then it should be possible to be objective in reviewing one's own relevant findings. In reviews written by multiple authors, this may be achieved by assigning the review of the results of a coauthor to different coauthors.

Rule 10: Be Up-to-Date, but Do Not Forget Older Studies

Given the progressive acceleration in the publication of scientific papers, today's reviews of the literature need awareness not just of the overall direction and achievements of a field of inquiry, but also of the latest studies, so as not to become out-of-date before they have been published. Ideally, a literature review should not identify as a major research gap an issue that has just been addressed in a series of papers in press (the same applies, of course, to older, overlooked studies (“sleeping beauties” [26] )). This implies that literature reviewers would do well to keep an eye on electronic lists of papers in press, given that it can take months before these appear in scientific databases. Some reviews declare that they have scanned the literature up to a certain point in time, but given that peer review can be a rather lengthy process, a full search for newly appeared literature at the revision stage may be worthwhile. Assessing the contribution of papers that have just appeared is particularly challenging, because there is little perspective with which to gauge their significance and impact on further research and society.

Inevitably, new papers on the reviewed topic (including independently written literature reviews) will appear from all quarters after the review has been published, so that there may soon be the need for an updated review. But this is the nature of science [27] – [32] . I wish everybody good luck with writing a review of the literature.

Acknowledgments

Many thanks to M. Barbosa, K. Dehnen-Schmutz, T. Döring, D. Fontaneto, M. Garbelotto, O. Holdenrieder, M. Jeger, D. Lonsdale, A. MacLeod, P. Mills, M. Moslonka-Lefebvre, G. Stancanelli, P. Weisberg, and X. Xu for insights and discussions, and to P. Bourne, T. Matoni, and D. Smith for helpful comments on a previous draft.

Funding Statement

This work was funded by the French Foundation for Research on Biodiversity (FRB) through its Centre for Synthesis and Analysis of Biodiversity data (CESAB), as part of the NETSEED research project. The funders had no role in the preparation of the manuscript.

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How to Write a Literature Review

Start drafting.

It’s time to start drafting your paper. Follow the structure from your outline and start filling in the missing parts. Get out your notes and remind yourself of the sources you plan to talk about. You don’t have to write your paper from beginning to end in order–you can go to the parts that feel the easiest and start there. Here are some places you can start:

Bullet-Point Draft

With a Bullet-Point draft you take the ideas you’ve been outlining and fill them in with more details but only in bullet-point form. The beauty of bullet points is that they keep you from getting caught up in the language and style and allow you to focus simply on your main points. You can smooth out the sentences and transitions later, but for now, just get your ideas on the page.

Write the Introduction

Another way to get started is to write the Introduction. You already have a thesis statement, so now you can start introducing your topic and its importance, setting up your literature review.

Write a Body Paragraph

Or a third place to start is to jump into writing a body paragraph that synthesizes your sources. Use your notes and outline, and choose one set to talk about in paragraph form.

Don’t think too hard about getting things perfect when you’re drafting–that’s what revision is for. Just focus on getting started. If you get stuck, do some brainstorming activities to get your creative juices flowing. Once you have something written, I suggest seeking feedback to make sure you’re going in the right direction. In fact, I recommend getting as much feedback as possible along the way.

As you create a draft, try to incorporate several sources into each paragraph to be sure that you’re synthesizing and not just summarizing or listing without making connections. Your color-coded notes can help you be sure that you’re synthesizing.

Add Metacommentary

Metacommentary is the key to synthesis. Metacommentary (aka metadiscourse) is a type of commentary that guides your reader and helps them interpret the sources and evidence you’re presenting. Think of it as really powerful transitions.

Transition words act like signposts–they guide your reader through your points. They can also glue your ideas together so they feel more cohesive. Beware that transitions can definitely be overdone, but most students in general could use more transitions in their papers rather than fewer.

You might think you can just stop at transition words, but metacommentary is much more than just sprinkling some “therefores” and “howevers” throughout your paper–metacommentary actually takes your synthesis to the next level. What do you comment on? You can either interpret why a source is important, highlight its significance, or connect it with other sources. This is your chance to point out the answers to the four questions you looked for in your note-taking:

What do researchers agree and disagree about?

How are researchers narrowing or changing their focus to create new information?

What are each study’s limitations and strengths?

What’s the next step in research—what should be studied in the future? (The research gap)

You can think of metacommentary as a sandwich with your name on it. If my student’s name were Alisa, here’s what and Alisa sandwich would look like:

ALISA-SOURCE-ALISA

First, Alisa starts with a claim about what’s happening in the field or about a particular subsection or focus of the field. This could serve as a topic sentence for a paragraph, for example.

Second, she sets up the source with guiding language like transitions and references to her past points or sources.

Third, she writes about the source itself and summarizes pertinent information.

Lastly, Alisa comments on the source and/or connects it to her main point or to next source.

This type of sandwich can occur several times in a paragraph as you synthesize your sources. Here’s a sample paragraph from Chris, a Public Health student, who wrote a paper called “The Causes of a Behavioral Pandemic: Screen-time Addiction and Consequent Depression Among Adolescents.” I’ve bolded the metacommentary Chris included to guide his readers and to connect his points.

Even though there have been far fewer studies on adolescents than adults , adolescent studies have consistently shown that those who are more physically active experience less depressive and associated symptoms, as well as a greater overall state of well-being (Kremer, 2014). These studies have also shown that low levels of vigorous exercise in youth can independently cause depressive symptoms. One longitudinal study revealed that over 30% of children who participate in high levels of screen-time use experience moderate to high levels of depressive symptoms (Kremer, 2014). Additionally, another study of children in the United States demonstrated that those who participated on a sports team were less likely to exceed recommended screen-time limits established by the US Department of Health. This study also demonstrated that as the number of total physical activity sessions increased among youth, both during free time and at organized events, children were less likely to exceed recommended screen-time limits (Carlson, 2010). In this study, children who were more physically active consistently showed lower rates of depression and other emotional disorders. Therefore, evidence across multiple studies suggests that participating in screen-time activity may not be the direct cause of depressive symptoms, but rather the sedentary lifestyle and lack physical activity it causes among youth. With this recent evidence, experts are beginning to search for ways to replace screen-time participation of adolescents with physical activities.

Note how the last few sentences of this paragraph consist entirely of metacommentary–points that connect to the bigger picture of Chris’s literature review. Also notice how Chris uses transition words and phrases to glue his points together so it doesn’t come out of the blue when he brings up a new study. Also, Chris discusses more than one study in this paragraph, demonstrating his ability to synthesize and not just summarize. Without the metacommentary, it would be much harder to see the connections between the studies and how they fit into the bigger picture. Finally, Chris indicates the implications of these studies and points to what researchers are doing next . This has a duel purpose of reminding readers why this topic is important as well as indicating where he will go in his next paragraph (about physical activities). Metacommentary is powerful!

Metacommentary takes practice, but you can do it! And it will not only make your points stronger, it will make it easier for your audience to read and understand–which should always be your goal.

If You Get Stuck

Literature reviews can be hard. If you get stuck, I have a little trick I tell my students. For your first draft, try starting every sentence with “Researchers . . .” I know this seems formulaic, but if you can keep your focus on what particular researchers did or what they agree or disagree on, you’ll avoid the most common pitfalls of literature reviews: sounding like a typical argumentative research paper. If your focus is always on what researchers are doing or what they’ve found, then at the very least you’ll stay in the realm of the literature review genre. Later you can go back through and change up your sentence structure, but I’ve found that this is an easy way for students to get through a first draft.

A Word on Verb Tense

The Real Last Step: Revise (and Revise and Revise)

Fantastic BYU Family Science professor Julie Haupt offers the following suggestions for doing four purposeful revisions–two global and two local.

GLOBAL REVISION–The Forest

Level 1: structural review (global).

Purpose: The structural review examines the document as a whole to see if all requirements are met and the document’s organization is sound.

Meet Assignment Requirements. Ask yourself if your paper meets all the requirements of the assignment? Look at your structure and make sure you have all necessary sections such as the following:

• Introduction (with Thesis Statement and/or Organizing Statement)

Body with Headings

Conclusion/Discussion

Include a Thesis and an Organizing Statement. Does the current version of the thesis statement match the tone, scope, and organization of the body text? Does an organizing statement after the thesis introduce the major topics and the order they will appear in the body (e.g., “This review will first discuss . . . then . . . and finally . . .)

Use Headings. Is the body text subdivided in a logical way with evidence-based information located in appropriate sections? Are the major sections roughly symmetrical (in terms of length)? Are the headings brief, yet descriptive? If subheadings are used, does the major section contain at least two? Are all levels of headings separated by text?

Level 2 (Global): Paragraph/Logic Review

Purpose: The Paragraph/Logic Review is designed to review each paragraph for cohesion and compliance to the CEC (Claim/Evidence/Commentary) format.

Sequence Paragraphs Effectively. When reading only the first sentence of each paragraph, does the logical pattern of the paper emerge? Do the claims made in these topic sentences coordinate well with the thesis of the paper?

Check Topic Sentences and Cohesion. Does the topic sentence or claim provide an effective overview of the information that is located in the paragraph? Is the claim supported by several points of synthesized evidence, rather than a single study? Does each paragraph seem well directed and cohesive? Do the sentences build one upon another within the paragraph in a logical way?

Evaluate Paragraph Length. Are any paragraphs too long (longer than approximately ½ page)? Are any paragraphs too short (approximately three sentences or less)? Do paragraphs transition well from one to the next and use transitional words to connect ideas?

LOCAL REVISION–The Tree

Level 3 (local): apa formatting review.

Purpose: The APA Formatting Review is designed to make sure all APA conventions are explicitly followed to help the paper reflect a high level of professionalism.

Check Document Formatting. Do the body text and reference page appear in the correct page formatting as required? (Use the APA Manual if you have questions.)

Examine the Reference List Closely. Are all references in the reference list ordered alphabetically? Is the reference list double spaced entirely (with no extra gaps between paragraphs)? Are all references (e.g., journal articles, internet resources, or books) listed in the correct format? Is every reference on the reference list cited at least once in the body and does each in-text citation have a corresponding reference in the reference list?

Make a Final Check of the In-Text Citations. Is all information properly cited with an in-text citation when needed? Do all in-text citations include the year next to the author(s)? When more than one citation is listed within parentheses are they separated by semi-colons and ordered alphabetically by first author’s last name? If included in parentheses, do studies with multiple authors use ampersands (“&” rather than the word “and”) before listing the last author?

Level 4 (Local): Finishing Review

Purpose: The Finishing Review is an opportunity to look closely at sentence construction, language, hedging , and grammar/punctuation.

Review Phrasing with a Read-Aloud Session. Since having to read a sentence twice to get its meaning or “tripping over” phrasing can be an indication of awkward construction, are all sentences easily read aloud? Are any sentences so long that they have become difficult to comprehend, but could be split without changing the meaning?

Use Non-Biased, Non-Absolute Language. Do all references to people comply with the “people first” designation and avoid inappropriate uses of terms for various groups? Are the findings and summary statements in the review properly “ Hedged ”?

Check Punctuation and Grammar. Are all commas, semicolons, colons, hyphens, and other punctuation used correctly throughout the document (including the reference page)? Are common grammar mistakes, such as parallelism, subject-verb agreement, incorrect misuse of pronouns, and other grammatical issues corrected?

*Bonus Video

If you’re still confused or would like more guidance on writing a literature review, here is an optional 25-minute video that thoroughly goes through the entire process of writing a literature review. As an extra bonus, it’s made by Michael Paye from the University of Dublin who has an awesome Irish accent. Enjoy!

Charles, C.C. (2020). How to write a literature review. In C.C. Charles (ed.), Writing in the Social Sciences. Edtech books. https://edtechbooks.org/writing/literature_review_2

Writing and the Sciences: An Anthology Copyright © 2020 by Sara Rufner is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License , except where otherwise noted.

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Reference to Published Sources of Information

Present Perfect Tense is often used when the focus of the work is on several authors.

Present Perfect Tense may also be used when you want to refer to how much or how little research has been carried out on a particular topic.

Present Tense is often used to refer to generally accepted scientific facts.

Modal Verbs may be used if you wish to introduce a degree of tentativeness into your comments about the work of an author. In this situation the reporting verb will be in the passive voice and the addition of a modal verb will indicate the degree of confidence attributed to the information.

Dissertations & projects: Tenses

• Research questions
• The process of reviewing
• Project management
• Literature-based projects

On this page:

“You will use a range of tenses depending on what you are writing about . ” Elizabeth M Fisher, Richard C Thompson, and Daniel Holtom,   Enjoy Writing Your Science Thesis Or Dissertation!

Tenses can be tricky to master. Even well respected journals differ in the guidance they give their authors for their use. However, their are some general conventions about what tenses are used in different parts of the report/dissertation. This page gives some advice on standard practice.

What tenses will you use?

There are exceptions however, most notably in the literature review where you will use a mixture of past , present and present perfect tenses (don't worry, that is explained below), when discussing the implications of your findings when the present tense is appropriate and in the recommendations where you are likely to use the future tense.

The tenses used as standard practice in each of these sections of your report are given and explained below.

In your abstract

You have some leeway with tense use in your abstract and guidance does vary which can sometimes be confusing. We recommend the following:

Describing the current situation and reason for your study

Mostly use the present tense,  i.e. "This is the current state of affairs and this is why this study is needed."

Occasionally, you may find the need to use something called the present perfect tense when you are describing things that happened in the past but are still relevant. The present perfect tense uses have/has and then the past participle of the verb i.e. Previous research on this topic has focused on... 

Describing the aims of your study

Here you have a choice. It is perfectly acceptable to use either the present or past tense,  i.e. "This study aims to..." or "This study aimed to..." 

Describing your methodology

Use the past tense to describe what you did, i.e. "A qualitative approach was used." "A survey was undertaken to ...". "The blood sample was analysed by..."

Describing your findings

Use the past tense to describe what you found as it is specific to your study, i.e. "The results showed that...", "The analysis indicated that..."

Suggesting the implications of your study

Use the present tense as even though your study took place in the past, your implications remain relevant in the present, i.e. Results revealed x which indicates that..."

Example abstract 

An example abstract with reasoning for the tenses chosen can be found at the bottom of this excellent blog post: 

Using the Present Tense and Past Tense When Writing an Abstract

In your methodology

The methodology is one of the easiest sections when it comes to tenses as you are explaining to your reader what you did. This is therefore almost exclusively written in the past tense.

Blood specimens were frozen at -80 o C.

A survey was designed using the Jisc Surveys tool.

Participants were purposefully selected.

The following search strategy was used to search the literature:

Very occasionally you may use the present tense if you are justifying a decision you have taken (as the justification is still valid, not just at the time you made the decision). For example: 

Purposeful sampling was used to ensure that a range of views were included. This sampling method maximises efficiency and validity as it identifies information-rich cases and ... (Morse & Niehaus, 2009).

In your discussion/conclusion

This will primarily be written in the present tense as you are generally discussing or making conclusions about the relevance of your findings at the present time. So you may write:

The findings of this research suggest that.../are potentially important because.../could open a new avenue for further research...

There will also be times when you use the past tense , especially when referring to part of your own research or previous published research research - but this is usually followed by something in the present tense to indicate the current relevance or the future tense to indicate possible future directions:

Analysis of the survey results found most respondents were not concerned with the processes, just the outcome. This suggests that managers should focus on...

These findings mirrored those of Cheung (2020), who also found that ESL pupils failed to understand some basic yet fundamental instructions. Addressing this will help ensure...

In your introduction

The introduction generally introduces what is in the rest of your document as is therefore describing the present situation and so uses the present tense :

Chapter 3  describes  the research methodology.

Depending on your discipline, your introduction may also review the literature so please also see that section below.

In your literature review

The findings of some literature may only be applicable in the specific circumstances that the research was undertaken and so need grounding to that study. Conversely, the findings of other literature may now be accepted as established knowledge. Also, you may consider the findings of older literature to be still relevant and relatively recent literature be already superseded. The tenses you write in will help to indicate a lot of this to the reader. In other words, you will use a mix of tenses in your review depending on what you are implying.

Findings only applicable in the specific circumstances

Use the past tense . For example: 

In an early study, Sharkey et al. (1991)  found  that isoprene emissions  were doubled  in leaves on sunnier sides of oak and aspen trees. 

Using the past tense indicates that you are not implying that isoprene emissions are always doubled on the sunnier side of the trees, just that is what was found in the Sharkey et al. study.

Findings that are still relevant or now established knowledge

Mostly use the present tense , unless the study is not recent and the authors are the subject of the sentence (which you should use very sparingly in a literature review) when you may need to use a mixture of the past and present. For example:

A narrowing of what 'graduateness' represents damages students’ abilities to thrive as they move through what will almost certainly be complex career pathways (Holmes, 2001).

Holmes (2001) argued strongly that a narrowing of what 'graduateness' represents damages  students’ abilities to thrive as they move through what will almost certainly be complex career pathways

Both of these imply that you think this is still the case (although it is perhaps more strongly implied in the first example). You may also want to use some academic caution too - such as writing 'may damage' rather than the more definite 'damages'.

Presenting your results

As with your methodology, your results section should be written in the past tense . This indicates that you are accepting that the results are specific to your research. Whilst they may have current implications, that part will not be considered until your discussion/conclusions section(s).

Four main themes were identified from the interview data.

There was a significant change in oxygen levels.

Like with the methodology, you will occasionally switch to present tense to write things like "Table 3.4 shows that ..." but generally, stick to the past tense.

In your recommendations

Not everyone will need to include recommendations and some may have them as part of the conclusions chapter. Recommendations are written in a mixture of the present tense and  future tense :

It is recommended that ward layout is adapted, where possible, to provide low-sensory bays for patients with autism. These will still be useable by all patients but...

Useful links

• Verb tenses in scientific manuscripts From International Science Editing
• Which Verb Tenses Should I Use in a Research Paper? Blog from WordVice
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Grammar: Verb Tenses

Most common verb tenses in academic writing.

According to corpus research, in academic writing, the three tenses used the most often are the simple present , the simple past , and the present perfect (Biber et al., 1999; Caplan, 2012). The next most common tense for capstone writers is the future ; the doctoral study/dissertation proposal at Walden is written in this tense for a study that will be conducted in the future.

Biber, D., Johansson, S., Leech, G., Conrad, S., & Finegan, E. (1999). Longman grammar of written and spoken English . Pearson. https://doi.org/10.1162/089120101300346831

Caplan, N. A. (2012). Grammar choices for graduate and professional writers . University of Michigan Press.

Simple present: Use the simple present to describe a general truth or a habitual action. This tense indicates that the statement is generally true in the past, present, and future.

• Example: The hospital admits patients whether or not they have proof of insurance.

Simple past : Use the simple past tense to describe a completed action that took place at a specific point in the past (e.g., last year, 1 hour ago, last Sunday). In the example below, the specific point of time in the past is 1998.

• Example: Zimbardo (1998) researched many aspects of social psychology.

Present perfect: Use the present perfect to indicate an action that occurred at a nonspecific time in the past. This action has relevance in the present. The present perfect is also sometimes used to introduce background information in a paragraph. After the first sentence, the tense shifts to the simple past.

• Example: Numerous researchers have used this method.
• Example: Many researchers have studied how small business owners can be successful beyond the initial few years in business. They found common themes among the small business owners.

Future: Use the future to describe an action that will take place at a particular point in the future (at Walden, this is used especially when writing a proposal for a doctoral capstone study).

• Example: I will conduct semistructured interviews.

Keep in mind that verb tenses should be adjusted after the proposal after the research has been completed. See this blog post about Revising the Proposal for the Final Capstone Document for more information.

APA Style Guidelines on Verb Tense

APA calls for consistency and accuracy in verb tense usage (see APA 7, Section 4.12 and Table 4.1). In other words, avoid unnecessary shifts in verb tense within a paragraph or in adjacent paragraphs to help ensure smooth expression.

• Use the past tense (e.g., researchers presented ) or the present perfect (e.g., researchers have presented ) for the literature review and the description of the procedure if discussing past events.
• Use the past tense to describe the results (e.g., test scores improved significantly).
• Use the present tense to discuss implications of the results and present conclusions (e.g., the results of the study show …).

When explaining what an author or researcher wrote or did, use the past tense.

• Patterson (2012) presented, found, stated, discovered…

However, there can be a shift to the present tense if the research findings still hold true:

• King (2010) found  that revising a document three times improves the final grade.
• Smith (2016) discovered that the treatment is effective.

Verb Tense Guidelines When Referring to the Document Itself

To preview what is coming in the document or to explain what is happening at that moment in the document, use the present or future tense:

• In this study, I will describe …
• In this study, I describe …
• In the next chapter, I will discuss …
• In the next chapter, I discuss …

To refer back to information already covered, such as summaries of discussions that have already taken place or conclusions to chapters/sections, use the past tense:

• Chapter 1 contained my original discussion of the research questions.
• In summary, in this section, I presented information on…

Simple Past Versus the Present Perfect

Rules for the use of the present perfect differ slightly in British and American English. Researchers have also found that among American English writers, sometimes individual preferences dictate whether the simple past or the present perfect is used. In other words, one American English writer may choose the simple past in a place where another American English writer may choose the present perfect.

Keep in mind, however, that the simple past is used for a completed action.  It often is used with signal words or phrases such as "yesterday," "last week," "1 year ago," or "in 2015" to indicate the specific time in the past when the action took place.

• I went to China in 2010 .
• He completed the employee performance reviews last month .

The present perfect focuses more on an action that occurred without focusing on the specific time it happened. Note that the specific time is not given, just that the action has occurred.

• I have travelled to China.

The present perfect focuses more on the result of the action.

• He has completed the employee performance reviews.

The present perfect is often used with signal words such as "since," "already," "just," "until now," "(not) yet," "so far," "ever," "lately," or "recently."

• I have already travelled to China.
• He has recently completed the employee performance reviews.
• Researchers have used this method since it was developed.

Summary of English Verb Tenses

The 12 main tenses:

• Simple present : She writes every day.
• Present progressive: She is writing right now.
• Simple past : She wrote last night.
• Past progressive: She was writing when he called.
• Simple future : She will write tomorrow.
• Future progressive: She will be writing when you arrive.
• Present perfect : She has written Chapter 1.
• Present perfect progressive: She has been writing for 2 hours.
• Past perfect: She had written Chapter 3 before she started Chapter 4.
• Past perfect progressive: She had been writing for 2 hours before her friends arrived.
• Future perfect: She will have written Chapter 4 before she writes Chapter 5.
• Future perfect progressive: She will have been writing for 2 hours by the time her friends come over.

Conditionals:

Zero conditional (general truths/general habits).

• Example: If I have time, I write every day.

First conditional (possible or likely things in the future).

• Example: If I have time, I will write every day.

Second conditional (impossible things in the present/unlikely in the future).

• Example : If I had time, I would write every day.

Third conditional (things that did not happen in the past and their imaginary results)

• Example : If I had had time, I would have written every day.

Subjunctive : This form is sometimes used in that -clauses that are the object of certain verbs or follow certain adjectives. The form of the subjective is the simple form of the verb. It is the same for all persons and number.

• Example : I recommend that he study every day.
• Example: It is important that everyone set a writing schedule.

Verbs Video Playlist

Note that these videos were created while APA 6 was the style guide edition in use. There may be some examples of writing that have not been updated to APA 7 guidelines.

• Grammar for Academic Writers: Common Verb Tenses in Academic Writing (video transcript)
• Grammar for Academic Writers: Verb Tense Consistency (video transcript)
• Grammar for Academic Writers: Advanced Subject–Verb Agreement (video transcript)
• Mastering the Mechanics: Helping Verbs (video transcript)
• Mastering the Mechanics: Past Tense (video transcript)
• Mastering the Mechanics: Present Tense (video transcript)
• Mastering the Mechanics: Future Tense (video transcript)

Related Resources

Knowledge Check: Verb Tenses

Didn't find what you need? Email us at [email protected] .

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Writing Resources

Verb tenses — literature.

Use of the correct verb tense allows you to express clearly the time relationships among your ideas. When deciding which verb tense to use, aim for consistency, simplicity and clarity.

Whenever possible, keep verbs in the same tense (consistency), and use either the simple present or the past tense (simplicity). Above all, choose the verb tense that most clearly expresses the idea you want to convey (clarity). In general, use the present tense to describe actions and states of being that are still true in the present; use the past tense to describe actions or states of being that occurred exclusively in the past.

Use the present tense to describe fictional events that occur in the text (this use of present tense is referred to as "the historical present"):

• In Milton's Paradise Lost, Satan tempts Eve in the form of a serpent.
• Voltaire's Candide encounters numerous misfortunes throughout his travels.

Also use the present tense to report your interpretations and the interpretations of other sources:

• Odysseus represents the archetypal epic hero.
• Flanagan suggests that Satan is the protagonist of Paradise Lost.

Use the past tense to explain historical context or elements of the author's life that occurred exclusively in the past:

• Hemingway drew on his experiences in World War I in constructing the character of Jake Barnes.

When writing about literature, use both present and past tense when combining observations about fictional events from the text (present tense) with factual information (past tense):

• James Joyce, who grew up in the Catholic faith, draws on church doctrine to illuminate the roots of Stephen Dedalus' guilt.
• In Les Belles Images, Simone de Beauvoir accurately portrays the complexities of a marriage even though she never married in her lifetime.

Use the present perfect tense to describe an event that occurs in the text previous to the principal event:

• The governess questions the two children because she believes they have seen the ghosts.
• Convinced that Desdemona has been unfaithful to him, Othello strangles her.

Use the past tense when referring to an event occurring before the story begins:

In the opening scenes of Hamlet, the men are visited by the ghost of Hamlet's father, whom Claudius murdered.

Adapted From: “Verb Tense,” Hamilton University Writing Center. 16 October 2017,

Works Cited:

• Webb, Suzanne, Robert Miller, and Winifred Horner. "Hodges' Harbrace Handbook," 14th edition. Fort Worth: Harcourt College Publishers, 2001.
• Zach Brown '03, and Sharon Williams would like to thank the following readers for their assistance in the preparation of this document: Meghan Barbour '00, John Farranto, '01, and Professors Eismeier, Grant, Hopkins, Jensen, J. O'Neill, Strout, Thickstun, and E. Williams.
• Professional Writing
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Using the Present Tense with Works; or, Othello Still Exists

It is customary to use the present tense when discussing a literary work:

Othello is a play by Shakespeare. It begins on a street in Venice, where Roderigo and Iago are arguing .

Some of the themes of Othello are racism, love, jealousy, and betrayal.

Like other Shakespearean tragedies, Othello has five acts.

The play ends with Othello’s murder of Desdemona and with the revelation of Iago’s motives.

Likewise, use the present tense to describe the actions of characters and the movement of plot:

In act 3 Iago persuades Othello that there is reason to doubt Desdemona’s faithfulness, and in the final act Othello confronts Desdemona and then strangles her to death.

The rationale for using the present tense when discussing a work is that the work exists in the present just as it existed earlier: Othello always has five acts and always ends with the same actions.

The principle applies to works of all sorts, from literary criticism to films to websites:

William Hazlitt’s Characters of Shakespeare’s Plays contrasts expressions of passion and violence in Othello and Macbeth .

A 1965 film version of Othello stars Laurence Olivier.

The blog Bard Film analyzes references to Shakespeare in popular films.

By extension, you may also use the present tense when the subject is not the work itself but the work’s author, if the work is implied. In the following examples, “in Othello ” is implied:

[In Othello ] Shakespeare gives Iago, an archetypal villain, an important role.

By identifying Othello as a Moor, Shakespeare introduces both racial and religious issues [in Othello ].

Acceptable Uses of the Past Tense

If you’re primarily discussing the historical context of a work, however, use the past tense:

By identifying Othello as a Moor, Shakespeare introduced both racial and religious issues to early modern playgoers.

Use care when choosing between the past and present tense. A good rule of thumb is to consider whether the principal context of your discussion is textual or historical.

When the context is clearly historical, the choice of the past tense is obvious:

Othello was first performed in 1604, at Whitehall Palace in London.

Shakespeare composed Othello about fifteen years after Marlowe wrote Tamberlaine .

Aim for Consistency

Above all, aim for consistency and try to avoid frequent shifts in tense, which can be jarring for readers. It’s easy to shift tenses without realizing it. Here’s an example that uses tenses inconsistently:

For the plot of Othello , Shakespeare adapts a sixteenth-century Italian tale, while Christopher Marlowe based his play Tamberlaine on the life of an Asian emperor.

In this sentence about the sources of Elizabethan dramatists it would be better to keep the verb tenses consistent and use adapted and based .

Here’s another example of tense shifting:

The details of Othello’s narrative come from medieval and early modern travel books, some of which described fantastic creatures.

The author uses the present tense for the main text under discussion, but for the other texts—the travel books—switches to the past tense. The switch is understandable: the travel books inspired Othello’s narrative in the past, when the narrative was created. Using the present tense consistently, however, would accurately reflect the status of all the texts mentioned in the sentence as works that exist in the present: The details of Othello’s narrative come from medieval and early modern travel books, some of which describe fantastic creatures.

A word of caution for copyeditors: if an author uses the past or present tense in a consistent manner when discussing works, pause before you follow an impulse to change the tenses, especially if such an intervention would be extensive. The author may have sound reasons for his or her choices, and you would do better to query before you impose one tense over another. If you encounter frequent shifting of tenses for no discernible reason, revising for consistency is a good idea.

marian 06 October 2019 AT 07:10 PM

When quoting literature that is originally written in the past tense, which tense should be used to introduce the text - present or past?

Example for essay on Edith Wharton's Ethan Frome: When Ethan and Mattie return from town, they, “passed into the kitchen, which had the deadly chill of a vault after the dry cold of the night."

Writing an academic essay for a Literature course, I should write in the present tense and I should be consistent with tense. Which rule applies here?

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Erika Suffern 07 October 2019 AT 08:10 AM

The way you have written it is correct. Don't change the verb tenses in quoted material.

Veronica M. Schuder 12 December 2020 AT 04:12 PM

The second use of this word, which occurs when Mrs Mallard sits down and “abandoned herself” (756), offers an alternative meaning.

That sounds wrong. Can I change the tense to present with brackets: “abandon[s] herself” (756). ?????

Erika Suffern 14 December 2020 AT 09:12 AM

The short answer is yes. For additional guidance, please see our post on changing verb tenses in quotations: https://style.mla.org/using-brackets-to-change-tense/

Professor Rosalind Horowitz 10 March 2021 AT 12:03 PM

In the study of ancient Judaic literature, for example, Rashi, a brilliant commentator of texts, we always use the present tense to show that the scholarship is not archaic but still relevant and useful to current life. It is a way of putting the text inside the contemporary world.

Sara 16 June 2022 AT 05:06 PM

When writing about a text in MLA should you write in simple present or present continuous? or does it not matter?

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