How to Write a Literature Review
Learn what a literature review is, where it is used, and the structure it should follow, including how to refer to studies and establish themes. We provides tips on writing a literature review, such as stating your research question, selecting key terms, and finding relevant literature on your topic.
Updated on May 17, 2023
A literature review is an overview of the existing literature on a particular topic. It provides a concise summary and critical analysis of existing publications. This justifies why the study was conducted. It also helps the reader understand the topic and see areas for future research. It can be part of a manuscript’s introduction section or a required part of an academic thesis. It can also be a standalone paper, such as a narrative review.
This article discusses what a literature review is when it’s part of a research paper. It provides strategies, tools, and tips for writing a good review.
What is a literature review, and where is it used?
A literature review is an organized summary of existing literature on a topic or research question. It’s used to help readers understand what has been done before related to the topic you’re writing on.
It shows how your study fits into the literature, why your study is needed, and what novel insights your study will bring to the literature.
In that sense, a literature review justifies your work and its potential impact. Literature reviews are also valuable for other researchers, as they can overview a specific topic.
A literature review is used in academic documents, including manuscripts, theses and dissertations, and in standalone papers such as systematic reviews and narrative reviews.
In a manuscript or dissertation, the literature review is presented as background information in the introduction section. Here, it summarizes prior research on the key concepts the paper focuses on, identifies gaps in the literature, and provides context for why the current study is needed. It focuses on summarizing articles that provide specific evidence relating to the topic of the larger manuscript and is very narrowly focused.
In contrast, a standalone literature review is a comprehensive and critical analysis of the existing research and literature on a specific topic. It synthesizes the current state of knowledge on the topic, identifies gaps, contradictions, and future directions for research. A literature review paper is typically longer, more comprehensive, and applies a study methodology.
What structure do literature reviews follow?
Literature reviews follow a logical structure, meaning every sentence logically leads to the next. They begin with a broad overview of the topic and then narrow down to specific research carried out on that topic in a way that builds on the previous information. Supporting studies are discussed one-by-one or they’re grouped by themes. They may or may not specifically indicate the authors by name. That depends on personal style and guidelines.
Referring to studies
For example, the literature review in Howden et al. (2018), reporting on a randomized controlled trial (RCT) on fitness and heart failure, first states the overall theme: sedentary aging’s association with worsening cardiovascular health. In concise sentences, it then lists the themes along with subscript numbers of the supporting literature, e.g., “...middle age is the strongest predictor of future heart failure.5–7”. No authors are named. This may be because of the referencing style (using numbers leading to the References list, unlike, for instance, APA, which uses last names), or it may be the authors’ preference.
Tramontano et al. (2021), on remote work, lists authors’ names along with the supporting research. In some cases, the names are in parentheses (per APA style) and in other cases, (e.g., ...Gonzales Vazquez and colleagues (2019) indicated...) the names represent the study. Again, it’s a combination of referencing style and authors’ preference.
As the literature review progresses, you synthesize the information from the articles. Articles are grouped together by theme or evidence (i.e., supporting or contrasting), with relevant citations giving support. Typically, findings are condensed and summarized concisely (i.e., in one or a couple of sentences).
For example, if you were exploring how processed food affects heart health, articles in the literature review might be grouped into categories such as heart health in general, processed foods, and the negative effects of processed foods on general heart health. You’d then summarize the key findings for each category with relevant citations.
As such, a literature review in a manuscript is not simply a chronological list of articles and their findings. Rather, it’s a report and analysis of the existing literature. It weaves a narrative that underpins your own study.
Writing your literature review
State your research question
The first step to writing a good literature review is stating your research question.
If you’re writing a manuscript or dissertation, you likely already know what your research question is. Be sure it’s clearly presented at the end of the introductory paragraph so the reader immediately knows what the study will be about.
Select key terms
Next, identify several key words/terms/phrases that will be used to query your search for relevant literature.
For example, if your manuscript is about the effects of processed foods on heart health, you will want to use keywords such as “cardiovascular,” “processed foods,” and “heart disease” to retrieve relevant publications.
Find relevant literature on your topic
Most researchers have a specialty or a few specialties. Reading other studies should already be part of your day-to-day practice. So it’s very unusual to start a literature review from zero. You probably already have a folder full of PDFs (or, ideally, a reference manager full of well-organized articles in digital format).
For your current research, you’ll then add further literature in more specific and specialized areas. You’ll need to update your personal library. And you may find you lack sufficient publications in a certain area of research. Your literature review will address all these issues. Methods for diving in include databases, review articles, and asking colleagues and other researchers.
Searching with databases often requires a combination of free and paid sources.
Google Scholar is probably the most commonly known search engine for academic literature because, well, it’s Google. Type titles, keywords, authors, or other entries to find papers on your topic of interest. You don’t need to create an account, but just because a publication is listed in Scholar doesn’t mean you can access the full text. Still, its powerful search features can help you rapidly narrow your search. You can then find publications in a database for which you have a subscription.
EBSCO and ProQuest are commonly available in universities’ online libraries, and databases like PubMed are comprehensive scientific collections. Some databases are open access, while others require a subscription to fully access the articles. Hopefully, you have access through your university or institution.
There are also publisher-managed search engines and databases like ScienceDirect or Scopus, as well as Wiley Online Library. These usually require a subscription.
Elicit is an AI-based search engine. Ask a research question and find relevant literature. It also suggests questions based on your input for better results. No account is needed.
Zendy is a search engine dedicated to open access journals. It’s accessible once you create an account.
Colleagues, fellow researchers
Asking your colleagues or fellow researchers in your field can be a great resource for finding additional studies. You can also look for highly cited papers in your field or search for articles from known experts in your field.
Other literature reviews, review articles, and reference lists
Previous review papers on your topic, introduction sections of articles (which contain their own literature reviews), are reference lists of papers are all great tools for finding additional articles. Look through the reference lists of previous prior review papers to locate other relevant articles.
With this approach, you’ll find yourself diving down one rabbit hole after another. And it can get overwhelming, so scan quickly, keep notes, and use a good reference manager (see below). After a while, you’ll start to see the same publications emerge. You’ll start to recognize the seminal pieces as well as highly specific studies on limited populations.
Software and reference managers
Apps like Connected Papers can help expand your collection and ensure you’re not missing any articles. With this tool, you can search for a work and then see it visualized through other articles it references, and that referenced it. It’s shown as a network of connected papers – fantastic for visual types.
Reference managers like EndNote and Mendeley are helpful tools for organizing your papers and adding citations to your manuscript. You can download them to your computer and easily search for the information you’ve read before, saving a lot of time in the writing process. While they both require creating an account, Mendeley is free. Paperpile is an excellent lighter-weight option.
Organize your sources
When you’ve compiled sufficient publications via your literature search, extract relevant information for your research question.
First, identify the most relevant papers for your research question. One good approach is to read the abstract and methods sections to understand the main findings.
Narrow down your list to articles that have a research question as similar as possible to yours. Then, group them by themes or evidence. For instance, group articles showing that processed foods lead to increased rates of heart disease in one section.
Include contradictory evidence to fully cover the scope of the topic. This will help you better organize the sections for your review later.
Define your key concepts
Every good review section begins with specific definitions of the concepts the paper will focus on. They should be defined in the abstract and introduction.
Write an outline
Write an outline with subheadings representing categories or themes your review will cover. Under each theme, enter a few references or key points that reflect what you want to convey to your reader in that section.
Organize the subheadings logically so that one idea flows into the next. Don’t jump back and forth between concepts. For example, if you’re establishing a common, evidence-supported definition of heart disease, focus only on that. Bringing in other diseases will confuse the reader. If you need to compare with other diseases, that’s probably cause for another subsection.
Review previous articles on your topic and check how the authors structured their introduction section to get ideas for your outline.
For longer reviews, you can use tables to present the literature and key themes more clearly for the reader. Tables are especially useful in dedicated review papers like narrative reviews.
Write your literature review
Following your outline, expand on your notes with sentences and paragraphs, including relevant citations (see the section above for examples of how these are typically written). Use clear and concise language. Make sure all your paragraphs have a dedicated topic sentence that reflects what the rest of the paragraph is about.
Start your review broadly, then use your prior research to narrow down to why your research question is needed. For example, define what heart disease is broadly, then narrow down to how specific processed foods can impact it and what still needs to be investigated (i.e., with your study).
Review your work
After finishing your first draft, revise and refine your work. Here are some key steps.
Refine your literature review
As you write, you may need to expand sections or include more evidence. Read over your review several times and determine if it’s conveying the information you want to get across clearly and adjust accordingly.
Omit unnecessary information
In scientific communication, less is more, so avoid making your review too long. Remove unnecessary information and avoid being too wordy. As a general rule, aim for just one idea per sentence and no more than around 15–20 words per sentence.
A credible citation (or citations) should support every assertion. But it can also get tempting to follow irrelevant paths that aren’t immediately relevant to the study you’re doing now.
Professional editing can also help you refine wordiness.
Check the logical structure
Check that each section in your review relates to the main research question. Check that every paragraph transitions smoothly to the next and that the ideas flow logically from one argument to the next. Ask yourself, “Does this idea directly relate to my next idea?” (and vice versa).
Also, check for consistency and completeness. Be sure you used the same wording for key concepts throughout your review and that you included all relevant evidence for your arguments.
Check for and remove/correct plagiarism
There are many ways to plagiarize, and some authors don’t even know when they’re doing it. It can be a critical mistake.
Journals use tools such as iThenticate to detect plagiarism. And being caught plagiarizing can be a cause for a rapid rejection. Avoid plagiarizing by ensuring you cite the original source and don’t copy/paste text unless you use quotation marks. You can check for plagiarism using apps like Grammarly or Trinka, which can also help you improve your writing style and correct grammar mistakes.
Get outside perspectives
Ask a senior researcher or colleague to read your work and provide feedback or criticism. Ask junior researchers as well. Put your ego on the line for the good of rigorous science. Often, those with less experience may be able to see the more basic gaps in logic and clarity, as they bring a less honed and specialized perspective.
Check that you’ve included all references in the format required by the journal (e.g., APA, Vancouver, AMA). Use tools like Mendeley and EndNote to automatically generate a bibliography section based on the references you enter in your document. But do double-check what the software generates. It may be relying on incorrect metadata.
Good example of a literature review in a published article
Good literature reviews should be clear, concise, and informative. They should present enough information on the topic that you can understand the importance of the topic, the relevance of the literature included for the broader field, and what’s still missing from the literature (i.e., where further research is needed).
Here’s a good example:
Heart issues, sedentary lifestyle, exercise (from Howden et al. 2018)
Readable and well-structured, this review quickly highlights the negative relationship between a sedentary lifestyle and heart issues. It concisely reviews previous literature showing the relationship between exercise and heart health, so the reader understands why the study is needed.
Bonus: What’s the difference between a literature review and an annotated bibliography?
An annotated bibliography is a list of references with a brief summary of the results of that reference. It can also include your personal notes on the study and why it’s relevant to your study.
Especially for students, a literature review can be confused with an annotated bibliography. Both these devices detail existing studies. However, they perform quite different functions.
Annotated bibliographies are powerful when you’re writing a dissertation or any longer research piece, as they help you keep track of everything you’ve read and why it’s relevant. You may not publish it, but you can definitely use it when you write your literature review.
So, the key differences between an annotated bibliography are:
- An annotated bibliography is a list of references with no connection established among them, while a literature review is a narrative of all the studies.
- Annotated bibliographies are organized alphabetically by reference, whereas literature reviews are organized by themes or supporting or contrasting evidence.
- Annotated bibliographies summarize (in a few sentences) each reference, while literature reviews place the publication in context along with other publications.