How to Write a Literature Review (Step-by-Step)

Common types of gaps:

• Empirical gaps: A phenomenon has not been studied in a particular context, population, or time period
• Methodological gaps: Existing studies use methods that cannot address a specific aspect of the question
• Theoretical gaps: Existing frameworks do not adequately explain observed phenomena
• Conceptual gaps: A concept is used inconsistently across the literature, creating confusion

Step 5: Write the Literature Review

Once you have your sources organized by theme and your gap identified, writing the review becomes a matter of building each section as an argument.

Opening: Scope and significance

The introduction to a literature review should:

• Define the topic and its scope
• Explain why this area of scholarship matters
• Preview the structure of the review (what themes or sections follow)

Avoid starting with "Many researchers have studied X" or "X has been studied for many years." These openings are vague and do not establish any analytical position.

Body: Theme sections

Each section of the body covers one major theme, debate, or methodological tradition. A strong body section:

• Opens with a sentence that names the theme and its significance
• Groups sources by what they argue, not by who wrote them
• Shows how sources relate to each other ("Building on Smith's finding, Jones argues...")
• Evaluates strengths and limitations of work in the section
• Ends by connecting the section to the overall gap or argument

Synthesis language is essential. Phrases that show you are synthesizing rather than summarizing:

• "Several studies find... However, this consensus is challenged by..."
• "Both Smith (2015) and Jones (2018) emphasize X, but they disagree on..."
• "While quantitative work has shown X, qualitative approaches complicate this by..."

Closing: The gap your research addresses

The conclusion of a literature review should bring all the themes together to establish the specific gap your research fills. It answers: given everything you have just reviewed, what question remains unanswered, and why is your approach to answering it the right one?

This closing paragraph is what makes the literature review function as a setup for the rest of the paper or dissertation rather than as a standalone exercise.

Common Literature Review Mistakes

Organizing chronologically. "In 1990, Researcher A said X. In 1995, Researcher B said Y. In 2000, Researcher C said Z" is a history of publication, not a literature review. Organize by argument, theme, or debate.

Summarizing without evaluating. Describing what researchers found without engaging critically with how they found it, whether it is reliable, and what it does not address is not a review. Evaluate the work, not just the findings.

Including sources to demonstrate breadth rather than relevance. Every source in your review should contribute to the argument. Sources cited only to show familiarity with the field pad the list without strengthening the review.

Failing to connect back to your own research. The literature review should build toward your research question. If a reader cannot see how your research fills a gap the review established, the review has not done its job.

Treating the literature review as complete before the dissertation is. Literature reviews are almost always revised late in the dissertation process once the final argument is clearer. The review you write in year 2 will be revised in year 4 to more precisely set up the argument your research actually produced.

Literature Reviews in Different Contexts

For PhD dissertations specifically, the literature review chapter (typically Chapter 2) is discussed in detail in the guide on how to write a PhD dissertation, including how it fits with your methods, findings, and conclusion.

Frequently Asked Questions

How long should a literature review be? Length depends on context. A PhD dissertation literature review is typically 10,000 to 20,000 words (30 to 60 pages). A journal article literature review might be 500 to 2,000 words. A standalone systematic review article may be 5,000 to 15,000 words. Ask your advisor or check examples in your field's leading journals.

Should I include everything I read? No. Include sources that contribute to the argument your review is making. Exclude sources that are tangential, methodologically too weak to be useful, or that simply repeat what better-cited work has already established. A focused 60-source review is stronger than an unfocused 150-source list.

What is the difference between a literature review and a systematic review? A systematic review follows a documented, reproducible protocol for searching and selecting sources, designed to minimize selection bias. It is a specific research method used primarily in health sciences, education, and social policy. A literature review (without "systematic") is a broader category that includes various approaches to synthesizing existing scholarship, with more flexibility in scope and method.

Can I use sources I did not read fully? You should not cite sources for specific claims if you have only read the abstract. If an article is highly relevant and frequently cited, read it fully. If it appears to support a general point that is already well established by sources you have read fully, an abstract may be sufficient for that specific use. When in doubt, read the paper.

How recent do sources need to be? For most academic fields, the bulk of your literature review should cite work from the last 10 to 15 years. Foundational, frequently cited work from earlier periods can be cited for historical context or for theoretical frameworks that have not been superseded. In rapidly changing fields (machine learning, some areas of biology), 5 years may be the practical horizon for "current."