How to Write a Literature Review (Structure, Synthesis, Examples)

Reviewed by Prof. Dr. Alexander Holtermann · Updated 16 October 2026 · 5 min read

A literature review synthesizes what research says about your topic, organized by themes, and shows the gap your study fills. It is not a list of summaries.

Key takeaways

A literature review synthesizes and evaluates; it does not summarize sources one by one.
Organize it thematically (by concepts, debates, or findings) in most cases; chronological or methodological structures suit some topics.
In a dissertation it is usually 20–30 % of the word count and ends with the research gap that justifies your research question.
Every paragraph should compare at least two sources: where they agree, where they differ, and why.
There are different types: the narrative review chapter in a dissertation, a standalone review paper, and the systematic review with an explicit, reproducible method.

What a literature review does

A literature review shows your reader what is already known about your topic, how researchers have approached it, where they agree and disagree, and what is still missing. It positions your own study in that landscape. In a dissertation it is typically Chapter 2; in a research paper it may be a section of the introduction; and in some courses it is a standalone assignment.

Examiners look for three things: coverage (you know the key work), critical evaluation (you judge quality and relevance, not just report), and synthesis (you connect sources into an argument that leads to your question).

One rule beats every guide on the internet, including this one: your own university’s or department’s style guide, handbook, or assignment brief always takes precedence. If it differs from what you read here, follow it. You can upload that handbook to Professor Digital, and everything (outline, citations, checks) is tailored to it.

Summary vs. synthesis

The difference between a weak and a strong literature review is almost always synthesis. A summary-based review goes source by source (“Smith found… Jones found… Lee found…”). A synthesis-based review goes idea by idea and brings several sources into each paragraph.

Summary (weak)	Synthesis (strong)
Organized by author	Organized by theme or question
“Smith (2019) found X. Jones (2021) found Y.”	“While early studies found X (Smith, 2019), more recent work with larger samples suggests Y (Jones, 2021; Lee, 2022).”
Describes	Compares, evaluates, explains differences
No clear endpoint	Leads to the gap and your research question

Ways to structure a literature review

Choose the structure that best serves your research question. Thematic structures work for most topics; you can combine them, for example themes with a chronological thread inside each theme.

Structure	Organized by	Good when
Thematic	Key concepts, debates, or findings	Most topics (default choice)
Chronological	Development over time	A field has clearly evolved, e.g., after a policy change
Methodological	Research approaches (surveys, experiments, interviews)	Methods explain differing results
Theoretical	Competing theories or models	You need to choose or build a framework

Step by step

Writing a literature review is a cycle of searching, reading, and organizing. These steps keep it under control.

1. Define scope: concepts, time frame, population, types of sources.
2. Search systematically in databases and use snowballing.
3. Read and take structured notes: aim, method, sample, findings, limitations, relevance.
4. Build a synthesis matrix: sources in rows, themes in columns.
5. Identify patterns: agreements, contradictions, gaps, methodological weaknesses.
6. Outline by themes and decide the order (general to specific).
7. Write paragraph by paragraph, each with a clear topic sentence.
8. End with the gap and the research question it justifies.

The synthesis matrix

A synthesis matrix is the most efficient tool to move from summaries to synthesis. List each source in a row and your themes in columns. Fill in briefly what each source says about each theme. Reading down a column shows you what the literature says about one theme, which is exactly what a paragraph needs.

Source	Effect on grades	Effect on well-being	Sample / context
Adams (2018)	Negative	–	US, 1,200 students
Brown & Clark (2020)	Negative above 20 h	Higher stress	US, survey
Davis (2021)	No effect below 15 h	–	Australia
Evans et al. (2022)	–	Mixed: income reduces stress	UK, interviews

Language for critical evaluation

Critical does not mean negative. It means judging strengths and weaknesses fairly and explaining what follows from them for your study. Use reporting verbs that reflect the author’s stance precisely.

Neutral: states, reports, describes, notes
Tentative: suggests, proposes, speculates
Strong: argues, demonstrates, shows, establishes
Critical: overlooks, fails to consider, is limited by
Comparative: consistent with, in contrast to, extends, challenges

Frequently asked questions

How long should a literature review be?

In a dissertation, typically 20–30 % of the total word count, for example 2,500–3,500 words in a 12,000-word undergraduate dissertation. Standalone review assignments follow the set word count.

How many sources should a literature review have?

There is no fixed number. Undergraduate dissertations often cite 25–50 sources in the review, master’s theses 40–80. Coverage of the key work matters more than the count.

What is the difference between a literature review and a systematic review?

A narrative literature review selects and synthesizes relevant work; a systematic review follows a predefined, reproducible search and selection protocol and reports it transparently.

Can I use first person in a literature review?

In APA style yes, for your own evaluations (“I argue that…”). Most of the review, however, focuses on the literature, so it naturally uses third person.

How do I end a literature review?

Summarize the main patterns, state the gap clearly, and show how your research question addresses it.

Sources and further reading

Booth, W. C., Colomb, G. G., Williams, J. M., Bizup, J., & FitzGerald, W. T. (2016). The Craft of Research (4th ed.). University of Chicago Press.
Swales, J. M., & Feak, C. B. (2012). Academic Writing for Graduate Students: Essential Tasks and Skills (3rd ed.). University of Michigan Press.

Your university’s examination regulations and style guide always take precedence.