How to Write a Literature Review: The Complete Guide

A literature review is one of the most important and most misunderstood sections of any academic essay or dissertation. Many students think a literature review is simply a summary of sources — it is not. It is a critical synthesis of existing research that demonstrates your understanding of the field, identifies gaps in knowledge and justifies your own research approach. This guide explains exactly how to write a literature review that impresses your markers.

What Is a Literature Review?

A literature review surveys, evaluates and synthesises existing academic research on a topic. Its purpose is to show what is already known, identify debates and contradictions in the field, highlight gaps your research will address, and position your work within the broader academic conversation. A good literature review does not just describe what each source says — it shows how sources relate to each other, where they agree and disagree, and what questions remain unanswered.

Step 1 — Search for Sources

Use academic databases to find peer-reviewed sources. The most useful include Google Scholar, JSTOR, PubMed (health and medicine), PsycINFO (psychology), Scopus and your university library database. Search using keywords related to your topic, and use Boolean operators to refine your results: AND (narrows results), OR (broadens results), NOT (excludes terms). Aim for sources published within the last 10 years unless you are reviewing foundational or historical literature. For a 3,000-word dissertation literature review, aim for at least 15 to 20 sources. Our guide on how to find credible academic sources covers this in detail.

Step 2 — Evaluate and Select Sources

Not all sources are equal. Evaluate each source using the CRAAP test: Currency (is it recent?), Relevance (does it relate to your topic?), Authority (is the author credible?), Accuracy (is the information supported by evidence?), Purpose (why was it written?). Prioritise peer-reviewed journal articles and academic books. Avoid websites, blogs and Wikipedia as primary sources.

Step 3 — Identify Themes and Gaps

Before writing, organise your sources by theme rather than by author. Look for patterns: Where do sources agree? Where do they contradict each other? What questions have not been answered? What methodologies have been used? Create a thematic map or table to organise your sources before you begin writing.

Step 4 — Choose a Structure

There are three main ways to structure a literature review: Thematic (organised by theme or concept — most common and recommended), Chronological (organised by publication date — useful for showing how thinking has evolved), or Methodological (organised by research method — useful for methodology-focused dissertations). Thematic structure is almost always the strongest choice for undergraduate and postgraduate essays.

Step 5 — Write and Synthesise

The key skill in a literature review is synthesis — combining ideas from multiple sources rather than describing them one by one. Instead of: "Smith (2020) found X. Jones (2021) found Y. Brown (2022) found Z." Write: "Research consistently shows X (Smith, 2020; Jones, 2021), although Brown (2022) challenges this finding by arguing Y." Use linking phrases to show relationships between sources: "Similarly...", "In contrast...", "Building on this work...", "This finding is supported by...", "However, critics argue..."

Common Mistakes to Avoid

• Summarising instead of synthesising — the most common error
• Including too many direct quotes — paraphrase and cite instead
• Ignoring contradictory evidence — acknowledge debates honestly
• Using non-academic sources — stick to peer-reviewed literature
• No clear structure — use themes, not a source-by-source approach
• Failing to link to your own research — always show how the literature relates to your study

FAQs

How long should a literature review be?

For a dissertation, the literature review is typically 15 to 25% of the total word count. For a 10,000-word dissertation, that is 1,500 to 2,500 words. For a standalone literature review assignment, follow your brief.

Should I include my own opinion in a literature review?

Yes — but carefully. You should evaluate and critique the sources rather than simply accepting them. However, avoid first-person statements unless your institution permits them. Use phrases like "this argument is limited by..." or "this evidence suggests..."