how many references for a literature review

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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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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.

• University of Oregon Libraries
• Research Guides

How to Write a Literature Review

• 4. Manage Your References
• Literature Reviews: A Recap
• Reading Journal Articles
• Does it Describe a Literature Review?
• 1. Identify the Question
• 2. Review Discipline Styles
• Searching Article Databases
• Finding Full-Text of an Article
• Citation Chaining
• When to Stop Searching

Manage your references

Why do i have to cite my sources, citation styles, major citation styles - official and credible guidance.

• 5. Critically Analyze and Evaluate
• 6. Synthesize
• 7. Write a Literature Review

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As p art of your lit review, you'll need to provide a list of references -- your professors want to know where  you found your information. 

Your professor will also require that you use a specific format ("style") for citing your references, such as one of these: 

• APA (American Psychological Association)
• Chicago Manual of Style
• MLA (Modern Language Association)

University Library provides an  online guide to help you cite your sources correctly   in multiple styles.

Citation styles

In academic writing, there are many different formats for citing the sources you use in your research. Here are a few of the most common, and their related disciplines.

Accessibility note: Below is a chart with two columns for format and discipline.

Note: Regardless of which format you use, you must include the same basic bibliographic information when citing a source.

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There are many different types of academic and professional writing styles. The four guidebooks below represent some of the major ones. Use these guides to learn how professional researchers and writers prepare their manuscripts for publication or sharing.

Online Style Resources

Although these resources are not official, they are still credible and very useful! If one of these websites doesn't answer your question, check out the official style guide or contact a librarian for help!

UO Research Guides

These helpful guided from UO Libraries provide information on various citation styles.

• Citation and Plagiarism by Genifer Snipes Last Updated May 3, 2024 2380 views this year
• Introductory How-To Tutorials for MLA and APA Styles from UO Libraries by Genifer Snipes Last Updated May 3, 2024 41 views this year
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• What is a Literature Review? | Guide, Template, & Examples

What is a Literature Review? | Guide, Template, & Examples

Published on 22 February 2022 by Shona McCombes . Revised on 7 June 2022.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research.

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarise sources – it analyses, synthesises, and critically evaluates to give a clear picture of the state of knowledge on the subject.

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Table of contents

Why write a literature review, examples of literature reviews, step 1: search for relevant literature, step 2: evaluate and select sources, step 3: identify themes, debates and gaps, step 4: outline your literature review’s structure, step 5: write your literature review, frequently asked questions about literature reviews, introduction.

• Quick Run-through
• Step 1 & 2

When you write a dissertation or thesis, you will have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and scholarly context
• Develop a theoretical framework and methodology for your research
• Position yourself in relation to other researchers and theorists
• Show how your dissertation addresses a gap or contributes to a debate

You might also have to write a literature review as a stand-alone assignment. In this case, the purpose is to evaluate the current state of research and demonstrate your knowledge of scholarly debates around a topic.

The content will look slightly different in each case, but the process of conducting a literature review follows the same steps. We’ve written a step-by-step guide that you can follow below.

Prevent plagiarism, run a free check.

Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research objectives and questions .

If you are writing a literature review as a stand-alone assignment, you will have to choose a focus and develop a central question to direct your search. Unlike a dissertation research question, this question has to be answerable without collecting original data. You should be able to answer it based only on a review of existing publications.

Make a list of keywords

Start by creating a list of keywords related to your research topic. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list if you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can use boolean operators to help narrow down your search:

Read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

To identify the most important publications on your topic, take note of recurring citations. If the same authors, books or articles keep appearing in your reading, make sure to seek them out.

You probably won’t be able to read absolutely everything that has been written on the topic – you’ll have to evaluate which sources are most relevant to your questions.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models and methods? Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• How does the publication contribute to your understanding of the topic? What are its key insights and arguments?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research.

You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review.

The scope of your review will depend on your topic and discipline: in the sciences you usually only review recent literature, but in the humanities you might take a long historical perspective (for example, to trace how a concept has changed in meaning over time).

Remember that you can use our template to summarise and evaluate sources you’re thinking about using!

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It’s important to keep track of your sources with references to avoid plagiarism . It can be helpful to make an annotated bibliography, where you compile full reference information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

You can use our free APA Reference Generator for quick, correct, consistent citations.

To begin organising your literature review’s argument and structure, you need to understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly-visual platforms like Instagram and Snapchat – this is a gap that you could address in your own research.

There are various approaches to organising the body of a literature review. You should have a rough idea of your strategy before you start writing.

Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarising sources in order.

Try to analyse patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organise your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text, your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

If you are writing the literature review as part of your dissertation or thesis, reiterate your central problem or research question and give a brief summary of the scholarly context. You can emphasise the timeliness of the topic (“many recent studies have focused on the problem of x”) or highlight a gap in the literature (“while there has been much research on x, few researchers have taken y into consideration”).

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, make sure to follow these tips:

• Summarise and synthesise: give an overview of the main points of each source and combine them into a coherent whole.
• Analyse and interpret: don’t just paraphrase other researchers – add your own interpretations, 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 transitions and topic sentences to draw connections, comparisons and contrasts.

In the conclusion, you should summarise the key findings you have taken from the literature and emphasise their significance.

If the literature review is part of your dissertation or thesis, reiterate how your research addresses gaps and contributes new knowledge, or discuss how you have drawn on existing theories and methods to build a framework for your research. This can lead directly into your methodology section.

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a dissertation , thesis, research paper , or proposal .

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarise yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your  dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

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How to write a superb literature review

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Literature reviews are important resources for scientists. They provide historical context for a field while offering opinions on its future trajectory. Creating them can provide inspiration for one’s own research, as well as some practice in writing. But few scientists are trained in how to write a review — or in what constitutes an excellent one. Even picking the appropriate software to use can be an involved decision (see ‘Tools and techniques’). So Nature asked editors and working scientists with well-cited reviews for their tips.

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Correction 09 December 2020 : An earlier version of the tables in this article included some incorrect details about the programs Zotero, Endnote and Manubot. These have now been corrected.

Hsing, I.-M., Xu, Y. & Zhao, W. Electroanalysis 19 , 755–768 (2007).

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Literature Reviews

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What is a literature review?

Why conduct a literature review, stages of a literature review, lit reviews: an overview (video), check out these books.

• Types of reviews
• 1. Define your research question
• 2. Plan your search
• 3. Search the literature
• 4. Organize your results
• 5. Synthesize your findings
• 6. Write the review
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Definition: A literature review is a systematic examination and synthesis of existing scholarly research on a specific topic or subject.

Purpose: It serves to provide a comprehensive overview of the current state of knowledge within a particular field.

Analysis: Involves critically evaluating and summarizing key findings, methodologies, and debates found in academic literature.

Identifying Gaps: Aims to pinpoint areas where there is a lack of research or unresolved questions, highlighting opportunities for further investigation.

Contextualization: Enables researchers to understand how their work fits into the broader academic conversation and contributes to the existing body of knowledge.

tl;dr  A literature review critically examines and synthesizes existing scholarly research and publications on a specific topic to provide a comprehensive understanding of the current state of knowledge in the field.

What is a literature review NOT?

❌ An annotated bibliography

❌ Original research

❌ A summary

❌ Something to be conducted at the end of your research

❌ An opinion piece

❌ A chronological compilation of studies

The reason for conducting a literature review is to:

Literature Reviews: An Overview for Graduate Students

While this 9-minute video from NCSU is geared toward graduate students, it is useful for anyone conducting a literature review.

Writing the literature review: A practical guide

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Writing literature reviews: A guide for students of the social and behavioral sciences

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Telling a research story: Writing a literature review

The literature review: Six steps to success

Systematic approaches to a successful literature review

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Literature Reviews: Overview

This video from NCSU Libraries gives a helpful overview of literature reviews. Even though it says it's "for graduate students," the principles are the same for undergraduate students too!

Reading a Scholarly Article

• Reading a Scholarly Article or Literature Review Highlights sections of a scholarly article to identify structure of a literature review.
• Anatomy of a Scholarly Article (NCSU Libraries) Interactive tutorial that describes parts of a scholarly article typical of a Sciences or Social Sciences research article.
• Evaluating Information | Reading a Scholarly Article (Brown University Library) Provides examples and tips across disciplines for reading academic articles.
• Reading Academic Articles for Research [LIBRE Project] Gabriel Winer & Elizabeth Wadell (ASCCC Open Educational Resources Initiative (OERI))

Literature Review Examples

What is a Literature Review?

The literature review is a written explanation by you, the author, of the research already done on the topic, question or issue at hand. What do we know (or not know) about this issue/topic/question?

• A literature review provides a thorough background of the topic by giving your reader a guided overview of major findings and current gaps in what is known so far about the topic. 
• The literature review is not a list (like an annotated bibliography) -- it is a narrative helping your reader understand the topic and where you will "stand" in the debate between scholars regarding the interpretation of meaning and understanding why things happen. Your literature review  helps your reader start to see the "camps" or "sides" within a debate, plus who studies the topic and their arguments. 
• A good literature review should help the reader sense how you will answer your research question and should highlight the preceding arguments and evidence you think are most helpful in moving the topic forward.
• The purpose of the literature review is to dive into the existing debates on the topic to learn about the various schools of thought and arguments, using your research question as an anchor. If you find something that doesn't help answer your question, you don't have to read (or include) it. That's the power of the question format: it helps you filter what to read and include in your literature review, and what to ignore.

How Do I Start?

Essentially you will need to:

• Identify and evaluate relevant literature (books, journal articles, etc.) on your topic/question.
• Figure out how to classify what you've gathered. You could do this by schools of thought, different answers to a question, the authors' disciplinary approaches, the research methods used, or many other ways.
• Use those groupings to craft a narrative, or story, about the relevant literature on this topic. 
• Remember to cite your sources properly! 
• Research: Getting Started Visit this guide to learn more about finding and evaluating resources.
• Literature Review: Synthesizing Multiple Sources (IUPUI Writing Center) An in-depth guide on organizing and synthesizing what you've read into a literature review.
• Guide to Using a Synthesis Matrix (NCSU Writing and Speaking Tutorial Service) Overview of using a tool called a Synthesis Matrix to organize your literature review.
• Synthesis Matrix Template (VCU Libraries) A word document from VCU Libraries that will help you create your own Synthesis Matrix.

Additional Tutorials and Resources

• UR Writer's Web: Using Sources Guidance from the UR Writing Center on how to effectively use sources in your writing (which is what you're doing in your literature review!).
• Write a Literature Review (VCU Libraries) "Lit Reviews 101" with links to helpful tools and resources, including powerpoint slides from a literature review workshop.
• Literature Reviews (UNC Writing Center) Overview of the literature review process, including examples of different ways to organize a lit review.
• “Ten Simple Rules for Writing a Literature Review.” Pautasso, Marco. “Ten Simple Rules for Writing a Literature Review.” PLOS Computational Biology, vol. 9, no. 7, July 2013, p. e1003149.
• Writing the Literature Review Part I (University of Maryland University College) Video that explains more about what a literature review is and is not. Run time: 5:21.
• Writing the Literature Review Part II (University of Maryland University College) Video about organizing your sources and the writing process. Run time: 7:40.
• Writing a Literature Review (OWL @ Purdue)
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• Next: Zotero >>

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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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• Last Updated: May 20, 2024 9:47 AM
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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 .

You Might Also Like:

38 Comments

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

This is awesome!

I wish I come across GradCoach earlier enough.

But all the same I’ll make use of this opportunity to the fullest.

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 🙂

This has been really helpful. Will make full use of it. 🙂

Thank you Gradcoach.

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Thank you so much for your guide of video and other instructions for the dissertation writing.

It is instrumental. It encouraged me to write a dissertation now.

Thank you the video was great – from someone that knows nothing thankyou

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It is timely

It is very good video of guidance for writing a research proposal and a dissertation. Since I have been watching and reading instructions, I have started my research proposal to write. I appreciate to Mr Jansen hugely.

I learn a lot from your videos. Very comprehensive and detailed.

Thank you for sharing your knowledge. As a research student, you learn better with your learning tips in research

I was really stuck in reading and gathering information but after watching these things are cleared thanks, it is so helpful.

Really helpful, Thank you for the effort in showing such information

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Thank you for this whole literature writing review.You have simplified the process.

I’m so glad I found GradCoach. Excellent information, Clear explanation, and Easy to follow, Many thanks Derek!

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

Thank you Coach, you have greatly enriched and improved my knowledge

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!

Thanks, Stephanie 🙂

This is mind blowing, the detailed explanation and simplicity is perfect.

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.

This is a very well thought out webpage. Very informative and a great read.

Very timely.

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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How many sources are enough? Six questions on breadth and depth of literature reviews

The first question I posed in the title of my blog post is one that all of my students (undergraduate and graduate) and most of my research assistants ask me: how do I know when I’ve read enough for a literature review? The answer is never clear cut, unfortunately. I am someone who loves reading, and who needs to read broadly because his own work is interdisciplinary . I’m also quite systematic in how I read , and I prefer to err on the side of having TOO MANY sources rather than be accused of not knowing the field.

I also realize not everyone has the time to be on top of the literature , particularly with teaching, service, family and caring and research obligations. I am going to answer the top six questions I get asked on breadth and depth of literature reviews, and in doing so, I am going to suggest a few shortcuts that may help narrowing a literature review search and finding the “sweet spot” where you’ve read enough that you feel confident enough to start writing your paper, chapter or thesis.

1. How many sources should I read for my literature review? This is an absurd question that is prompted by arbitrarily setting a random number of sources as “enough”. If you read the right five sources, you’ve probably covered a full field. But if you read 40 sources that all tend to pull in different directions, you’ll still be unable to cover all the sources.

Here’s my totally non-scientific take for coursework-related materials: a final research paper should at least use 13 additional sources to those in the syllabus (one additional paper per week) for an undergraduate class, and an in-depth literature review for a graduate course should be in the realm of 26 (2 additional papers per week) to 39 (3 additional papers per week for PhD students) . If somebody writes a final paper for my courses that only use the readings we did during the semester, it shows they didn’t go any further and I’ll probably penalize them.

2. Where do I get sources for my literature review if I am starting up a new topic? Well, here are a couple of strategies:

There are 2 clear sources of citations for literature reviews: (1) papers that are systematic reviews or meta-reviews pic.twitter.com/sYCUGv3kg0 — Dr Raul Pacheco-Vega (@raulpacheco) June 18, 2017

• Read literature summaries and reviews published in journals. There’s plenty of journals now that provide reviews of the literature. Three I’m well aware of are WIRES (Wiley Interdisciplinary Reviews) and Geography Compass, as well as Progress in Human Geography. When reading Progress in Human Geography, you probably want to look for the “Progress Reports”.
• Search for “a review of the literature” or “a meta-review” type of article s (either Google Scholar or other online databases). These articles will usually provide a pretty extensive range of sources. Given their goal and scope, they’re also probably comprehensive enough. Meta-reviews tend to be more synthetic and provide a research agenda and specific research questions that need to be looked at in future research.
• Ask specialists (or look for their work) for key citations from where you can do citation tracing . For example, if I were to do a search on water ethics, I would ask Christiana Peppard, Jeremy Schmidt, Lucy Rodina for suggestions. Or I would look for articles citing them. If I were to do something on climate politics, I’d look for Kathryn Harrison, Sarah Burch, Max Boykoff, Mat Patterson.

(2) papers that are "a literature review of" (this should be obvious, but a lot of people don't seem to know this!) pic.twitter.com/T1xaK2yvv9 — Dr Raul Pacheco-Vega (@raulpacheco) June 18, 2017

Also the scoping review, a derivative of systematic reviews that is meant to be broader and more exploratory: https://t.co/WQjEpnuZR3 — AJ Wray (@WrayAJ) June 18, 2017

3. “When should I stop reading and start writing?”

My answer to that question is: you should be reading AND writing . Apparently, a lot of people feel like they need to Read All The Things before they can write a literature review. That’s why I always suggest that when you process a reading (a PDF or a printed source), you should generate at the very minimum a row entry in your Excel conceptual synthesis , and a synthetic note (or a rhetorical precis ). Obviously, you gain a lot more if you write a full-fledged memo , but you may want to wait to write the memo up until you’ve read a few sources. But you should ALWAYS be writing as you read. You may not assemble the full literature review , but at least you can start with an annotated bibliography .

4. How do I know when to stop reading/researching/seeking more sources? This is again a very tough question. Having mapped a very broad survey of the literature on informal waste picking, I can assure you that I felt I could not stop even after reading 50 articles. There is just simply too much published. But one of the reasons why I encourage my students to stop when they reach conceptual saturation (e.g. when they start seeing the same themes repeated over and over again) is because I don’t think you gain too much, marginally, from reading yet another paper on the same topic but using a different case study.

For example, I recently wrote a series of memorandums on the urban commons. I had basically mapped the entire body of works on urban commons using the first 10 citations I found on Google Scholar. However, I wanted to see how much more I could go in depth on the topic. What I found was that there were many case studies, but all using the same conceptual framework. So that’s when I stopped. When I saw that basically every other paper was a variation of the same central 10 ones, but using different case studies. I added those sources to my bibliography, but I didn’t need to incorporate them to my literature review.

Another way to respond to this question is: read enough to answer your questions properly.

The two biggest questions that probably would encompass the previous ones are related to breadth and depth.

5. How far reaching should your literature review be? Scoping a literature review, as Dr. Pat Thomson shows here , is not an easy task. It requires us to search through many months or even years of published literature. I always do Google Scholar searches at least 7 years into the past (e.g. 2010 articles would totally be welcome, as would be books published in 2010) because of the very long lag-time that exists between submission, acceptance and publication. My citation tracing process also looks at the last 7 years of scholarship of key authors.

Then you have the other associated question – what about the “seminal” (I prefer the word fundamental) articles or books?

For me, this is the most challenging component. When I know a field very well (for example, agenda-setting theory in public policy), I can easily decide which authors I will be seeking (Stuart Soroka, Michael Howlett, Baumgartner and Jones, Kingdon). If I am doing policy design, I’ll go with Helen Ingram, Ann Schneider, etc. And then based on doing a citation tracing exercise , I will go to those younger scholars who are citing these key authors. But again, this requires you to know the field already.

This is where a supervisor, a coauthor, a colleague or a trusted scholar on Twitter may be helpful with narrowing the search scope. You can ask “ who are the key authors I should be reading on Topic A ” or “ which are the key citations I should be looking at to get a grasp of Field B “. And then use those authors to create a map of the literature .

And the last question, which just about everyone asks me:

6. Do I need to do an in-depth reading of All The Things? This is completely a question that has arbitrary answers and a broad range of parameters to work around. It also depends on what type of literature review you are writing. If you are, for example, preparing your doctoral comprehensive examinations, you DO want to read EVERYTHING and do so IN DEPTH . You need to demonstrate that you know your field of study, broadly and deeply.

However, if you are writing a literature review, for example, of agenda-setting theory and its applications to health policy, you may want to read in depth 5-10 articles on health policy, 5-7 articles on agenda-setting theory, and then start writing from there. Again, in-depth reading is correlated with the extent and degree to which you need to demonstrate that you know a field.

My method, as most people may have noticed, is usually as follows:

• I read 5-10 citations that I find key. This reading is usually in-depth.
• I create the set of questions I want to answer. I choose 3-5 citations around each question. All the reading associated with these questions I do using the AIC method , or skimming and scribbling unless I find key ones that need to be read in depth.
• I write a memorandum for each one of the questions I’m trying to answer. In this memorandum, I assemble a mini-literature review that answers the question.
• I fuse all the memorandums into a larger document where I have mapped out how each question (and answer) relates to the overall topic.
• I read my entire literature review and restart with citation tracing until I reach concept saturation .

Hopefully this post will help those who are struggling with literature reviews, as the summer approaches! You may also want to revisit my Literature Review posts .

You can share this blog post on the following social networks by clicking on their icon.

Posted in academia , research .

Tagged with literature review .

By Raul Pacheco-Vega – June 17, 2017

5 Responses

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Thank you so much for helping me to demistify the concept of approaching/ attempting to write a LitReview. This has helped me so much

So glad this is helpful!

This is exactly what I needed today, thank you!!

This was a great article! Thank you so much for sharing the knowledge.

I am currently on a year out from studying at undergrad level due to ill health but when I was studying, I was frequently demoralised by how hard I found it to capture my understanding of the material in my written work. I was assured that it would come with practice, and given writing guide books like Strunk’s “Elements of Style” but I didn’t feel like I was making progress. Given it’s only undergrad, the bar for written work is quite low, but I was anxious that my writing skills would hold me back, especially if I chose to go into post-grad research; it never felt like I was getting enough writing practice while actually studying. This really hit me last year’s exams when due to distance learning, instead of producing one uncited essay in 3 hours, I was expected to spend around 5-6 hours in a 48 hour window writing a fully sourced essay. I realised how ill-equipped I was to do focussed reading and note-taking, having previously been able to consume entire topics of content in my own time.

I’m so glad to have stumbled across your blog. I’m not due to resume studying for another year, but the techniques and strategies you describe here provide an effective starting point for practicing the research skills I feel lacking in. Having a clear starting point for skills based work makes me feel actively motivated to start working on it during this year off from formal studying. Thank you for producing this content.

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Researching and writing for Economics students

4 literature review and citations/references.

Figure 4.1: Literature reviews and references

Your may have done a literature survey as part of your proposal. This will be incorporated into your dissertation, not left as separate stand-alone. Most economics papers include a literature review section, which may be a separate section, or incorporated into the paper’s introduction. (See organising for a standard format.)

Some disambiguation:

A ‘Literature survey’ paper: Some academic papers are called ‘literature surveys’. These try to summarise and discuss the existing work that has been done on a particular topic, and can be very useful. See, for example, works in The Journal of Economic Perspectives, the Journal of Economic Literature, the “Handbook of [XXX] Economics”

Many student projects and undergraduate dissertations are mainly literature surveys.

4.1 What is the point of a literature survey?

Your literature review should explain:

what has been done already to address your topic and related questions, putting your work in perspective, and

what techniques others have used, what are their strengths and weaknesses, and how might they be relevant tools for your own analysis.

Figure 4.2: Take notes on this as you read, and write them up.

4.2 What previous work is relevant?

Focus on literature that is relevant to your topic only.

But do not focus only on articles about your exact topic ! For example, if your paper is about the relative price of cars in the UK, you might cite papers (i) about the global automobile market, (ii) about the theory and evidence on competition in markets with similar features and (iii) using econometric techniques such as “hedonic regression” to estimate “price premia” in other markets and in other countries.

Consider: If you were Colchester a doctor and wanted to know whether a medicine would be effective for your patients, would you only consider medical studies that ran tests on Colchester residents, or would you consider more general national and international investigations?

4.3 What are “good” economics journal articles?

You should aim to read and cite peer-reviewed articles in reputable economics journals. (Journals in other fields such as Finance, Marketing and Political Science may also be useful.) These papers have a certain credibility as they have been checked by several referees and one or more editors before being published. (In fact, the publication process in Economics is extremely lengthy and difficult.)

Which journals are “reputable”? Economists spend a lot of time thinking about how to rank and compare journals (there are so many papers written about this topic that they someone could start a “Journal of Ranking Economics Journals”. For example, “ REPEC ” has one ranking, and SCIMAGO/SCOPUS has another one. You may want to focus on journals ranked in the top 100 or top 200 of these rankings. If you find it very interesting and relevant paper published somewhere that is ranked below this, is okay to cite it, but you may want to be a bit more skeptical of its findings.

Any journal you find on JSTOR is respectable, and if you look in the back of your textbooks, there will be references to articles in journals, most of which are decent.

You may also find unpublished “working papers”; these may also be useful as references. However, it is more difficult to evaluate the credibility of these, as they have not been through a process of peer review. However, if the author has published well and has a good reputation, it might be more likely that these are worth reading and citing.

Unpublished “working papers”

You may also find unpublished “working papers” or ‘mimeos’; these may also be useful as references. In fact, the publication process in Economics is so slow (six years from first working paper to publication is not uncommon) that not consulting working papers often means not being current.

However, it is more difficult to evaluate the credibility of this ‘grey literature’, as they have not been through a process of peer review. However, if the author has published well and has a good reputation, it might be more likely that these are worth reading and citing. Some working paper series are vetted, such as NBER; in terms of credibility, these might be seen as something in between a working paper and a publication.

Which of the following are “peer-reviewed articles in reputable economics journals”? Which of the following may be appropriate to cite in your literature review and in your final project? 8

Klein, G, J. (2011) “Cartel Destabilization and Leniency Programs – Empirical Evidence.” ZEW - Centre for European Economic Research Discussion Paper No. 10-107

Spencer, B. and Brander, J.A. (1983) “International R&D Rivalry and Industrial Strategy”, Review of Economic Studies Vol. 50, 707-722

Troisi, Jordan D., Andrew N. Christopher, and Pam Marek. “Materialism and money spending disposition as predictors of economic and personality variables.” North American Journal of Psychology 8.3 (2006): 421.

The Economist,. ‘Good, Bad And Ugly’. Web. 11 Apr. 2015. [accessed on…]

Mecaj, Arjola, and María Isabel González Bravo. “CSR Actions and Financial Distress: Do Firms Change Their CSR Behavior When Signals of Financial Distress Are Identified?.” Modern Economy 2014 (2014).

Universities, U. K. “Creating Prosperity: the role of higher education in driving the UK’s creative economy.” London Universities UK (2010).

4.4 How to find and access articles

You should be able to find and access all the relevant articles online. Leafing through bound volumes and photocopying should not be neededs. (Having been a student in the late 90’s and 2000’s, I wish I could get those hours back.)

Figure 4.3: The old way!

Good online tools include Jstor (jstor.org) and Google Scholar (scholar.google.co.uk). Your university should have access to Jstor, and Google is accessible to all (although the linked articles may require special access). You will usually have the ‘most access’ when logged into your university or library computing system.If you cannot access a paper, you may want to consult a reference librarian.

It is also ok, if you cannot access the journal article itself, to use the last working paper version (on Google scholar find this in the tab that says “all X versions”, where X is some number, and look for a PDF). However, authors do not always put up the most polished versions, although they should do to promote open-access. As a very last resort, you can e-mail the author and ask him or her to send you the paper.

When looking for references, try to find ones published in respected refereed economics journals (see above ).

4.5 Good starting points: Survey article, course notes, and textbooks

A “survey article” is a good place to start; this is a paper that is largely a categorization and discussion of previous work on a particular topic. You can often find such papers in journals such as

• the Journal of Economic Perspectives,
• the Journal of Economic Surveys,
• and the Journal of Economic Literature.

These will be useful as a “catalog” of papers to read and considers citing. They are also typically very readable and offer a decent introduction to the issue or the field.

It is also helpful to consult module (course) notes and syllabi from the relevant field. Do not only limit yourself to the ones at your own university; many of universities make their course materials publicly accessible online. These will not only typically contain reading lists with well-respected and useful references, they may also contain slides and other material that will help you better understand your topic and the relevant issues.

However, be careful not to take material from course notes without properly citing it. (Better yet, try to find the original paper that the course notes are referring to.)

Textbooks serve as another extremely useful jumping off point. Look through your own textbooks and other textbooks in the right fields. Textbooks draw from, and cite a range of relevant articles and papers. (You may also want to go back to textbooks when you are finding the articles you are reading too difficult. Textbooks may present a simpler version of the material presented in an article, and explain the concepts better.)

4.6 Backwards and forwards with references

When you find a useful paper, look for its “family.” You may want to go back to earlier, more fundamental references, by looking at the articles that this paper cited. See what is listed as “keywords” (these are usually given at the top of the paper), and “JEL codes”. Check what papers this paper cites, and check what other papers cited this paper. On Google scholar you can follow this with a link “Cited by…” below the listed article. “Related articles” is also a useful link.

4.7 Citations

Keep track of all references and citations

You may find it helpful to use software to help you manage your citations

A storage “database” of citations (e.g., Jabref, Zotero, Endnote, Mendeley); these interface well with Google Scholar and Jstor

An automatic “insert citation” and “insert bibliography” in your word processing software

Use a tool like Endnote to manage and insert the bibliographies, or use a bibliography manager software such as Zotero or Jabref,

Further discussion: Citation management tools

List of works cited

Put your list of references in alphabetical order by author’s last name (surname).

Include all articles and works that you cite in your paper; do not include any that you don’t cite.

Avoiding plagiarism and academic offenses**

Here is a definition of plagiarism

The main point is that you need to cite everything that is not your own work. Furthermore, be clear to distinguish what is your own work and your own language and what is from somewhere/someone else.

Why cite? Not just to give credit to others but to make it clear that the remaining uncited content is your own.

Here are some basic rules:

(Rephrased from University of Essex material, as seen in Department of Economics, EC100 Economics for Business Handbook 2017-18, https://www1.essex.ac.uk/economics/documents/EC100-Booklet_2017.pdf accessed on 20 July 2019, pp. 15-16)

Do not submit anything that is not your own work.

Never copy from friends.

Do not copy your own work or previously submitted work. (Caveat: If you are submitting a draft or a ‘literature review and project plan’ at an earlier stage, this can be incorporated into your final submission.

Don’t copy text directly into your work, unless:

• you put all passages in quotation marks: beginning with ’ and ending with ’, or clearly offset from the main text
• you cite the source of this text.

It is not sufficient merely to add a citation for the source of copied material following the copied material (typically the end of a paragraph). You must include the copied material in quotation marks. … Ignorance … is no defence.’ (ibid, pp. 15 )

(‘Ibid’ means ‘same as the previous citation’.)

Your university may use sophisticated plagiarism-detection software. Markers may also report if the paper looks suspect

Before final submission, they may ask you to go over your draft and sign that you understand the contents and you have demonstrated that the work is your own.

Not being in touch with your supervisor may put you under suspicion.

Your university may give a Viva Voce oral exam if your work is under suspicion. It is a cool-sounding word but probably something you want to avoid.

Your university may store your work in its our database, and can pursue disciplinary action, even after you have graduated.

Penalties may be severe, including failure with no opportunity to retake the module (course). You may even risk your degree!

Comprehension questions; answers in footnotes

True or false: “If you do not directly quote a paper you do not need to cite it” 9

You should read and cite a paper (choose all that are correct)… 10

• If it motivates ‘why your question is interesting’ and how it can be modeled economically
• Only if it asks the same question as your paper
• Only if it is dealing with the same country/industry/etc as you are addressing
• If it has any connection to your topic, question, or related matters
• If it answers a similar question as your paper
• If it uses and discusses techniques that inform those you are using

4.8 How to write about previous authors’ analysis and findings

Use the right terminology.

“Johnson et al. (2000) provide an analytical framework that sheds substantial doubt on that belief. When trying to obtain a correlation between institutional efficiency and wealth per capita, they are left with largely inconclusive results.”

They are not trying to “obtain a correlation”; they are trying to measure the relationship and test hypotheses.

“Findings”: Critically examine sources

Don’t take everything that is in print (or written online) as gospel truth. Be skeptical and carefully evaluate the arguments and evidence presented. Try to really survey what has been written, to consider the range of opinions and the preponderance of the evidence. You also need to be careful to distinguish between “real research” and propaganda or press releases.

The returns to higher education in Atlantis are extremely high. For the majority of Atlanian students a university degree has increased their lifetime income by over 50%, as reported in the “Benefits of Higher Education” report put out by the Association of Atlantian Universities (2016).

But don’t be harsh without explanation:

Smith (2014) found a return to education in Atlantis exceeding 50%. This result is unlikely to be true because the study was not a very good one.

“Findings:” “They Proved”

A theoretical economic model can not really prove anything about the real world; they typically rely on strong simplifying assumptions.

Through their economic model, they prove that as long as elites have incentives to invest in de facto power, through lobbying or corruption for example, they will invest as much as possible in order to gain favourable conditions in the future for their businesses.

In their two period model, which assumes \[details of key assumptions here\] , they find that when an elite Agent has an incentive to invest in de facto power, he invests a strictly positive amount, up to the point where marginal benefit equals marginal cost”

Empirical work does not “prove” anything (nor does it claim to).

It relies on statistical inference under specific assumptions, and an intuitive sense that evidence from one situation is likely to apply to other situations.

“As Smith et al (1999) proved using data from the 1910-1920 Scandanavian stock exchange, equity prices always increase in response to reductions in corporate tax rates.”

“Smith et al (199) estimated a VAR regression for a dynamic CAP model using data from the 1910-1920 Scandanavian stock exchange. They found a strongly statistically significant negative coefficient on corporate tax rates. This suggests that such taxes may have a negative effect on publicly traded securities. However, as their data was from a limited period with several simultaneous changes in policy, and their results are not robust to \[something here\] , further evidence is needed on this question.”

Use the language of classical 11 statistics:

Hypothesis testing, statistical significance, robustness checks, magnitudes of effects, confidence intervals.

Note that generalisation outside the data depends on an intuitive sense that evidence from one situation is likely to apply to other situations.

“Findings”: How do you (or the cited paper) claim to identify a causal relationship?

This policy was explained by Smith and Johnson (2002) in their research on subsidies and redistribution in higher education. Their results showed that people with higher degree have higher salaries and so pay higher taxes. Thus subsidizing higher education leads to a large social gain.

The results the student discusses seem to show an association between higher degrees and higher salaries. The student seems to imply that the education itself led to higher salaries. This has not been shown by the cited paper. Perhaps people who were able to get into higher education would earn higher salaries anyway. There are ways economists used to try to identify a “causal effect” (by the way, this widely used term is redundant as all effects must have a cause), but a mere association between two variables is not enough

As inflation was systematically lower during periods of recession, we see that too low a level of inflation increases unemployment.

Economists have long debated the nature of this “Phillips curve” relationship. There is much work trying to determine whether the association (to the extent it exists) is a causal one. We could not rule out reverse causality, or third factor that might cause changes in both variables.

4.9 …Stating empirical results

Don’t write: “I accept the null hypothesis.”

Do write: “The results fail to reject the null hypothesis, in spite of a large sample size and an estimate with small standard errors” (if this is the case)

Note: The question of what to infer from acceptance/rejection of null hypotheses is a complex difficult one in Classical (as opposed to Bayesian) statistics. This difficulty is in part philosophical: classical hypothesis testing is deductive , while inference is necessarily inductive.

4.10 What to report

You need to read this paper more clearly; it is not clear what they conclude nor what their evidence is.

4.11 Organising your literature review

A common marking comment:

These papers seem to be discussed in random order – you need some structure organising these papers thematically, by finding, by technique, or chronologically perhaps.

How should you organise it? In what order?

Thematically (usually better)

By method, by theoretical framework, by results or assumptions, by field

Chronologically (perhaps within themes)

Exercise: Compare how the literature review section is organized in papers you are reading.

Figure 4.4: Organising a set of references

Q: What sort of structure am I using in the above outline?

It may also be helpful to make a ‘table’ of the relevant literature, as in the figure below. This will help you get a sense of the methods and results, and how the papers relate, and how to assess the evidence. You may end up putting this in the actual paper.

Figure 4.5: Organisational table from Reinstein and Riener, 2012b

4.12 What if you have trouble reading and understanding a paper?

Consult a survey paper, textbook, or lecture notes that discuss this paper and this topic

Try to find an easier related paper

Ask your supervisor for help; if he or she can

Try to understand what you can; do not try to “fake it”

4.13 Some literature survey do’s and don’ts

Do not cite irrelevant literature.

Do not merely list all the papers you could find.

Discuss them, and their relevance to your paper.

What are their strengths and weaknesses? What techniques do they use, and what assumptions do they rely on? How do they relate to each other?

Use correct citation formats.

Try to find original sources (don’t just cite a web link).

Don’t just cut and paste from other sources. And make sure to attribute every source and every quote. Be clear: which part of your paper is your own work and what is cited from others? The penalties for plagiarism can be severe!

• Critically examine the sources, arguments, and methods

4.14 Comprehension questions: literature review

How to discuss empirical results: “Causal” estimation, e.g., with Instrumental Variables

Which is the best way to state it? 12

“As I prove in table 2, more lawyers lead to slower growth (as demonstrated by the regression analysis evidence).”

“Table 2 provides evidence that a high share of lawyers in a city’s population leads to slower growth.”

3.“Table 2 shows that a high share of lawyers in a city’s population is correlated with slower growth.”

Which is better? 13

• “However, when a set of observable determinants of city growth (such as Census Region growth) are accounted for, the estimate of this effect becomes less precise.”
• “In the correct regression I control for all determinants of city growth and find that there is no effect of lawyers on growth”

Stating empirical results: descriptive

“Using the US data from 1850-1950, I find that inflation is lower during periods of recession. This is statistically significant in a t-test [or whatever test] at the 99% level, and the difference is economically meaningful. This is consistent with the theory of …, which predicts that lower inflation increases unemployment. However, other explanations are possible, including reverse causality, and unmeasured covarying lags and trends.”

“I find a significantly lower level of inflation during periods of recession, and the difference is economically meaningful. This relationship is statistically significant and the data is accurately measured. Thus I find that inflation increases unemployment.”

Some tips on writing a good paper– relevant to literature reviews

• Answer the question
• Provide clear structure and signposting
• Demonstrate an ability for critical analysis
• Refer to your sources
• Produce a coherent, clear argument
• Take time to proofread for style and expresssion
• Source “Assignment Writing Skills EBS 3rd year 2012”"

Answer: only b is a ‘peer reviewed article in a reputable economics journal’. All of these might be useful to cite, however. ↩

False. You need to cite any content and ideas that are not your own. ↩

Answers: 1, 5, and 6. Note that 2 and 3 are too narrow criteria, and 4 is too broad. ↩

or Bayesian if you like ↩

The second one; if this is really causal evidence. ↩

The first one. There is no ‘correct regression’. It is also not really correct in classical statistics to ‘find no effect’. ↩

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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

Writing a literature review.

The following guide has been created for you by the  Student Learning Advisory Service . For more detailed guidance and to speak to one of our advisers, please book an  appointment  or join one of our  workshops . Alternatively, have a look at our  SkillBuilder  skills videos.   

Preparing a literature review involves:

• Searching for reliable, accurate and up-to-date material on a topic or subject
• Reading and summarising the key points from this literature
• Synthesising these key ideas, theories and concepts into a summary of what is known
• Discussing and evaluating these ideas, theories and concepts
• Identifying particular areas of debate or controversy
• Preparing the ground for the application of these ideas to new research

Finding and choosing material

Ensure you are clear on what you are looking for. ask yourself:.

• What is the specific question, topic or focus of my assignment?
• What kind of material do I need (e.g. theory, policy, empirical data)?
• What type of literature is available (e.g. journals, books, government documents)?

What kind of literature is particularly authoritative in this academic discipline (e.g. psychology, sociology, pharmacy)?

How much do you need?

This will depend on the length of the dissertation, the nature of the subject, and the level of study (undergraduate, Masters, PhD). As a very rough rule of thumb – you may choose 8-10 significant pieces (books and/or articles) for an 8,000 word dissertation, up to 20 major pieces of work for 12-15,000 words, and so on. Bear in mind that if your dissertation is based mainly around an interaction with existing scholarship you will need a longer literature review than if it is there as a prelude to new empirical research. Use your judgement or ask your supervisor for guidance.

Where to find suitable material

Your literature review should include a balance between substantial academic books, journal articles and other scholarly publications. All these sources should be as up-to-date as possible, with the exception of ‘classic texts’ such as major works written by leading scholars setting out formative ideas and theories central to your subject. There are several ways to locate suitable material:

Module bibliography: for undergraduate dissertations, look first at the bibliography provided with the module documentation. Choose one or two likely looking books or articles and then scan through the bibliographies provided by these authors. Skim read some of this material looking for clues: can you use these leads to identify key theories and authors or track down other appropriate material?

Library catalogue search engine: enter a few key words to capture a range of items, but avoid over-generalisations; if you type in something as broad as ‘social theory’ you are likely to get several thousand results. Be more specific: for example, ‘Heidegger, existentialism’. Ideally, you should narrow the field to obtain just a few dozen results. Skim through these quickly to identity texts which are most likely to contribute to your study.

Library bookshelves: browse the library shelves in the relevant subject area and examine the books that catch your eye. Check the contents and index pages, or skim through the introductions (or abstracts, in the case of journal articles) to see if they contain relevant material, and replace them if not. Don’t be afraid to ask one of the subject librarians for further help. Your supervisor may also be able to point you in the direction of some of the important literature , but remember this is your literature search, not theirs.

Online: for recent journal articles you will almost certainly need to use one of the online search engines. These can be found on the ‘Indexing Services’ button on the Templeman Library website. Kent students based at Medway still need to use the Templeman pages to access online journals, although you can get to these pages through the Drill Hall Library catalogue. Take a look as well at the Subject Guides on both the Templeman and DHL websites.

Check that you have made the right selection by asking:

• Has my search been wide enough to ensure that I have identified all the relevant material, but narrow enough to exclude irrelevant material?
• Is there a good enough sample of literature for the level (PhD, Masters, undergraduate) of my dissertation or thesis?
• Have I considered as many alternative points of view as possible?
• Will the reader find my literature review relevant and useful?

Assessing the literature

Read the material you have chosen carefully, considering the following:

• The key point discussed by the author: is this clearly defined
• What evidence has the author produced to support this central idea?
• How convincing are the reasons given for the author’s point of view?
• Could the evidence be interpreted in other ways?
• What is the author's research method (e.g. qualitative, quantitative, experimental, etc.)?
• What is the author's theoretical framework (e.g. psychological, developmental, feminist)?
• What is the relationship assumed by the author between theory and practice?
• Has the author critically evaluated the other literature in the field?
• Does the author include literature opposing their point of view?
• Is the research data based on a reliable method and accurate information?
• Can you ‘deconstruct’ the argument – identify the gaps or jumps in the logic?
• What are the strengths and limitations of this study?
• What does this book or article contribute to the field or topic?
• What does this book or article contribute to my own topic or thesis?

As you note down the key content of each book or journal article (together with the reference details of each source) record your responses to these questions. You will then be able to summarise each piece of material from two perspectives:     

Content: a brief description of the content of the book or article. Remember, an author will often make just one key point; so, what is the point they are making, and how does it relate to your own research project or assignment?

Critical analysis: an assessment of the relative strengths and weaknesses of the evidence used, and the arguments presented. Has anything conveniently been left out or skated over? Is there a counter-argument, and has the author dealt with this adequately? Can the evidence presented be interpreted another way? Does the author demonstrate any obvious bias which could affect their reliability? Overall, based on the above analysis of the author’s work, how do you evaluate its contribution to the scholarly understanding and knowledge surrounding the topic?    

Structuring the literature review

In a PhD thesis, the literature review typically comprises one chapter (perhaps 8-10,000 words), for a Masters dissertation it may be around 2-3,000 words, and for an undergraduate dissertation it may be no more than 2,000 words. In each case the word count can vary depending on a range of factors and it is always best, if in doubt, to ask your supervisor.

The overall structure of the section or chapter should be like any other: it should have a beginning, middle and end. You will need to guide the reader through the literature review, outlining the strategy you have adopted for selecting the books or articles, presenting the topic theme for the review, then using most of the word limit to analyse the chosen books or articles thoroughly before pulling everything together briefly in the conclusion.

Some people prefer a less linear approach. Instead of simply working through a list of 8-20 items on your book review list, you might want to try a thematic approach, grouping key ideas, facts, concepts or approaches together and then bouncing the ideas off each other. This is a slightly more creative (and interesting) way of producing the review, but a little more risky as it is harder to establish coherence and logical sequencing.

Whichever approach you adopt, make sure everything flows smoothly – that one idea or book leads neatly to the next. Take your reader effortlessly through a sequence of thought that is clear, accurate, precise and interesting. 

Writing up your literature review

As with essays generally, only attempt to write up the literature review when you have completed all the reading and note-taking, and carefully planned its content and structure. Find an appropriate way of introducing the review, then guide the reader through the material clearly and directly, bearing in mind the following:

• Be selective in the number of points you draw out from each piece of literature; remember that one of your objectives is to demonstrate that you can use your judgement to identify what is central and what is secondary.
• Summarise and synthesise – use your own words to sum up what you think is important or controversial about the book or article.
• Never claim more than the evidence will support. Too many dissertations and theses are let down by sweeping generalisations. Be tentative and careful in the way you interpret the evidence.
• Keep your own voice – you are entitled to your own point of view provided it is based on evidence and clear argument.
• At the same time, aim to project an objective and tentative tone by using the 3rd person, (for example, ‘this tends to suggest’, ‘it could be argued’ and so on).
• Even with a literature review you should avoid using too many, or overlong, quotes. Summarise material in your own words as much as possible. Save the quotes for ‘punch-lines’ to drive a particular point home.
• Revise, revise, revise: refine and edit the draft as much as you can. Check for fluency, structure, evidence, criticality and referencing, and don’t forget the basics of good grammar, punctuation and spelling.

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How Many References in a Research Paper?

Junior researchers frequently wonder how many references should be included in their research papers. The common response? “As many as you need.” What exactly does that mean? While we admit there are very few hard-set rules regarding this issue, in this article, we will try to provide more concrete guidelines that will help you assess whether you have enough references in your paper.

Before we do so, let us briefly explain why references matter and whether the number of references you include can project certain perceptions about the quality of your work. There is such a thing as having too many or too few.

Why are research paper references and citations necessary?

References show that you have carefully reviewed the relevant literature and are now contributing something  novel  to the academic community. You establish authority and credibility when you can critically assess other literature and distinguish your findings from previous works (if any exist). We emphasize “critically assess” in the last sentence because references are only as good as you apply them to your research. Therefore, the famous adage “quality over quantity” is the key to deciding how many references are sufficient.

Likewise, citing your references within the research paper itself (in the form of academic citations ) is crucial in any academic work that makes assertations based on external studies. Failing to cite your sources can result in plagiarism, which even if accidental can still have some devastating consequences for academic researchers hoping to publish their work or finish graduate school.

Number of Sources Used Can Impact Perceptions of Quality

We would be remiss if we didn’t tell you that being at either extreme (having too few or too many references) can reflect poorly on your intellectual aptitude and your study’s validity. Here’s why:

• If you don’t have enough references, particularly on a topic familiar to a wide audience, readers may think that you haven’t done enough research into existing literature. Surely someone else has thought about related topics or used similar techniques. If you’re sloppy in conducting your diligence, readers will wonder whether your paper is worth reading. What’s novel and valuable about your paper? Were you just as sloppy with conducting your study? The answers to these questions need to be evident.
• Additionally, readers might be concerned that you may have plagiarized by failing to properly cite information. Unless you’re John Nash, who cited only two texts in his seminal  26-page PhD thesis  (one of which was to his prior work), ensure that you’ve properly researched the relevant papers and included appropriate citations! Especially, make sure that you have found, read, and included all the latest publications on your topic before finalizing and submitting your own paper—if the drafting process took some time, new literature might have come out in the meantime, and you don’t want to give the editor the impression that you are not on top of the newest developments.
• If you have too many references, readers may wonder if you did any original research at all. Unless you’re writing a literature review, your paper’s primary focus should be on your investigation and findings. Don’t bury your hard work under strings of citations and discussion regarding other works. Show your readers what you’ve discovered and how the new information you present fits into or departs from the academic community’s current understanding of your topic.

Additionally, let us highlight the difference between the number of references versus citations. References are the source materials; therefore, each reference should be listed only once in your references section. Citations are meant to identify the source of the information you use in your paper. You can cite a reference multiple times. Therefore, the number of citations you have is typically larger than the number of references an average paper includes. The opposite situation should never happen!

Key Factors Influencing the Number of References You Use

The following are some of the many factors that may influence the number of references you use:

• The number of references required for a paper will depend largely on your work’s purpose . For example, literature and systematic reviews are surveys of existing studies. Therefore, their reference lists will be more exhaustive than those of research papers whose primary focus is the current authors’ findings. Indeed, if you examine many journals’ author guidelines , you’ll note that journals have a higher maximum reference limit for review articles than original research papers.
• The length of your reference list will also depend on your research paper’s subject matter . For example, if you are writing about a field that is less studied (such as a subfield of neuroparasitology) you may discover that there aren’t many papers to cite. Similarly, newer fields will have fewer published papers that can be referenced. If you find yourself in this situation, review the references used by relevant current literature and see if you can expand your research, and thus your reference list, with valuable content from there.
• Another factor will be your  institution or journal’s requirements . If you are preparing a dissertation or thesis, double-check your department’s requirements. While rare, they may have specific limits. More commonly, journals restrict the number of references due to printing constraints.
• It may happen that you don’t have  access to certain literature  that could have served as a reference. In such a situation, you may wish to look for an institution that may be able to provide you access to that literature for the purposes of reviewing the content or contact one of the authors directly and ask for a copy.
• Given that more papers are being published than ever before in most fields, it is likely that reference lists will grow longer simply because there are more data and discussions of existing data available to cite . Keep track of changes to the size of reference lists in publications related to your field.
• Finally, a paper’s length bears some correlation to the number of references.

So how many references should be included?

Below, we provide tips on how to decide if you have enough resources. We also provide some general reminders on how to effectively use references. After all, references are meant to enhance your paper while still maintaining your research as the focal point.

Use academic journals as a guide

• One way to gauge how many references you should have is to survey academic journals for your article type in your field. Review their author guidelines for limits on the number of references for your article type, and make sure your reference list complies with those journal restrictions.
• Read recent articles relevant to your topic; check how many references other authors have included in their papers for the same article type as yours, and how frequently those works were cited per page.
• Keep in mind that the above methods will give you an estimate of how many references you should include overall but will not tell you how many citations you’ll need per page. The latter is impossible to state simply because certain sections may have no citations at all (the results section , for example).

Statistics regarding the number of references and citations

To give you a general idea, the following are some estimates from a couple of studies that examined the citation characteristics of articles published in various disciplines.

According to  Milojević’s study  encompassing research in the fields of astronomy, mathematics, robotics, ecology, and economics, the highest and average number of references per article page were as follows:

• Ecology: highest, ~58; average reference per page, 6;
• Math and robotics: highest, ~28; average reference per page, <1; and
• Economics: highest, ~ 32; average reference per page, >1 but <2.

The above findings were based on data compiled from the first 20 years of the author’s research. Since then some fields have increased the number of references. Thus, make sure to examine your target journal’s most recent and relevant publications for a better idea of how many references to include based on the specific type of article you plan to write.

In another study by Falagas et al. (2013),  medical journals averaged  29 references for articles that were 7.88 pages long (as printed in journals).

Finally, although the sample size was small (63 journals), Gali Halevi observed the following citation trends of a broader range of disciplines.

• The average number of references per article was the highest for the social sciences, physics, and astronomy, and arts & humanities (roughly 54 references per article).
• On the other hand, health professions and earth and planetary sciences had the fewest references per article at an average of 8 and 17 references, respectively.
• Math and engineering averaged at roughly 29 references per article.
• Biochemistry, genetics and molecular and other biological sciences averaged at 51.
• Hard and natural sciences more frequently cited recent literature while social sciences and math were likely to include older sources.

Note that the Halevi study is limited in size, fails to factor in article type and does little to account for variances across different fields and journals. For example, it is possible that more review articles could have been reviewed for certain fields than others. With that said, we provide the above information to provide a rough estimate.

At the end of the day, please keep in mind the requirements of your institution or target journal and the general trends for your specific article type (by examining the most recent relevant publications).

For additional information regarding journal restrictions on the number of references, read this article on ways to grow your publication list .

Some Dos and Don’ts for Reference Citation

• Don’t repeat references within a reference list.
• Don’t repeatedly cite yourself. Make sure to balance your discussion with external literature citations.
• Be careful about citing old references. The rule of thumb is to go back at most five to six years. Exceptions to this rule should be reserved for “seminal” works relevant to explaining what prompted your research. Roughly 85% of all cited works should be less than five years old.
• Be careful not to cite several references in one place  without  discussing the relevance of each work to your research. In other words, don’t say, “We referred to previous studies in this field (1-7)” unless you later explain how each of reference #s 1-7 apply to your discussion.
• Confirm the quality of the work you cite. Are there any ethical issues regarding the paper that would disqualify it as a good source? Do your references come from reputable sources such as respected journals rather than random blogs and website links? Remember that your analysis is only as good as the verifiable information you use to conduct your research.
• One of the main purposes of citing existing literature is to show the “knowledge gap” regarding your topic. Therefore, make sure the works you reference naturally lead readers to wonder about the research question you address in your paper. To explain further, think about your favorite fictional story. A successfully written story only reveals the background information needed for the reader to follow along in the story. You’ll rarely see an author waste time writing about how the main character stubbed his toe one day while going to work unless that event relates to an important aspect of the story. Similarly, the references you cite should support the story building you create in your research paper.
• Don’t completely ignore the paper that could disprove your hypothesis. You want to show objectivity and that you took a balanced and unbiased approach to conducting your research. Mention the potentially conflicting evidence and explain why you believe it is flawed or inapplicable to your research.
• In qualitative research papers, you may have fewer references.
• Anything you cite in your paper should be listed in the references section (or reference list). Anything listed as a reference should have been quoted or paraphrased in the text. If either rule is violated, something is wrong.
• Finally, remember that a paper will typically have more citations in the Introduction section and Discussion section than in other parts.

Wordvice Academic Resources

If you need help with paraphrasing text from the sources you cite to avoid plagiarism, with different citation styles , or with finding the perfect journal to submit your paper to, then have a look at our collection of articles on the Wordvice academic resources website . We also recommend our professional English editing and proofreading services , including paper editing and academic editing services to ensure that your writing is free of errors before submitting your manuscript to a journal.

Literature reviews

• Starting your literature review
• Introduction

Structuring your reading

When to stop reading, how to organise a literature review, writing your literature review.

• Developing your literature review
• Writing systematic reviews

Useful links for literature reviews

• Study Advice Helping students to achieve study success with guides, video tutorials, seminars and one-to-one advice sessions.

• Doing your literature review (video) Watch this brief video tutorial for more on the topic.
• Doing your literature review (transcript) Read the transcript.
• Literature searching guide A guide to finding articles, books and other materials on your subject. Includes tips on constructing a comprehensive search using search operators (AND/OR), truncation and wildcards.
• Doing your literature search video - University of Reading Brief video on literature searching from our Academic Liaison Librarians.
• Royal Literary Fund: Writing a Literature Review A guide to writing literature reviews from the Royal Literary Fund
• What it means to be a critical student A brief and very useful video tutorial from the University of Leicester.
• Reading and notemaking LibGuide Expert guidance on managing your reading and making effective notes.
• Dissertations and major projects LibGuide Expert guidance on planning, researching and writing dissertations and major projects.

If you have thought about the areas you need to research and have conducted some searches for literature, you should be ready to set down some draft topic headings to structure your literature review.

Select one of your headings and choose a few key texts to read first - three is ideal to start with. Remember that you may eventually be writing about the same text under different headings, so bear that in mind when you are reading and making notes.

When you have finished reading your chosen texts, write a draft section summarising and commenting on what you have read, taking special care to show how it is relevant to your research. Then look to see what you need to discuss further, and do more reading to enable you to plug the gaps.

Try to set limits on how long you will spend reading. Then plan backwards from your deadline and decide when you need to move on to other parts of your investigation e.g. gathering the data.

You need to show you have read the major and important texts in your topic, and that you have also explored the most up-to-date research. If you have demonstrated both of these, you are on the right lines.

If you keep coming across very similar viewpoints and your reading is no longer providing new information, this is a sign you have reached saturation point and should probably stop.

Be guided by your research questions. When reading, ask yourself, "How does this relate to my investigation?" If you are going off into unrelated areas, stop reading and refocus on your topic.

Another thing you can do is to group what you have read into different topics or themes . These can provide useful headings when you come to write up your literature review. Use different coloured highlighters to identify which topic or heading each article fits into.

Be selective - you don't have to include everything you have read in your literature review. Only include research which is relevant and which helps you understand more about your own investigation. What you leave out won't be wasted as it helped you refine your understanding of the wider issues and identify what was relevant to your own investigation.

You don't have to refer to everything in the same depth in your literature review. You are usually expected to prioritise recent research. Some scientific research that was crucial in the past is now out of date. For instance, there may be a few older studies that were important in starting research in the field, but their methods have been surpassed by more accurate methods. You only need to demonstrate your awareness of these older, dated studies in a few sentences, then move on to discussing in greater depth the up-to-date methods and why they are more accurate.

Like an essay, a literature review has an introduction, main body, and conclusion.

Introduction : This explains the broad context of your research area and the main topics you are investigating. It briefly highlights the relevant issues or debates that have characterised your field of research.

It should also include some signposting for the reader, explaining the organisation / sequence of topics covered, and the scope of your survey.

Main body : An analysis of the literature according to a number of themes or topics that overlap with your research. It may have headings.

You can write your literature review one section at a time, but make sure you read through them all to check they link together and tell a coherent "story".

This should show how your research builds on what has been done before. Based on previous research, you provide justifications for what you are doing, why you are doing it, and how you are going to do it.

Conclusion : This should summarise the current state of the research in your field as analysed in the main body. It should identify any gaps or problems with the existing research, and explain how your investigation is going to address these gaps or build on the existing research.

• The structure of a literature review (Royal Literary Fund) Guidance on structuring a literature review.
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• Last Updated: May 14, 2024 8:47 AM
• URL: https://libguides.reading.ac.uk/literaturereview