Literature review: from summary to synthesis

The literature review is often the hardest chapter to get right. Many students read dozens of papers, then write one paragraph per paper. The result is long, descriptive and gets comments like 'too descriptive' or 'be more critical'.

The difference between a weak and a strong literature review is one word: synthesis. Instead of reporting what each author said, you bring sources together to show what the field knows, where it disagrees, and what is missing.

Summary vs synthesis: what is the difference?

A summary tells the reader what one source says. Synthesis connects several sources to make a point of your own.

Choose a structure: thematic is usually best

There are a few common ways to organise a literature review. For most dissertations, a thematic structure works best because it lets you compare older and newer sources within each theme.

• Thematic: grouped around key themes, concepts or debates. Best for most dissertations.
• Chronological: shows how thinking developed over time. Useful when the history of an idea matters.
• Methodological: grouped by the methods researchers used. Useful when you want to show a gap in how a topic has been studied.

You can also combine them. For example, a thematic review might briefly trace the history of each theme before comparing recent studies.

Use a synthesis matrix

A synthesis matrix is a simple table that university writing centres recommend for exactly this problem. Put your themes down the side and your sources across the top. As you read each source, note what it says about each theme in the matching cell. Add a final column where you write your own observation about each theme.

1. 01

   List your sources

   Start with the 10 to 20 most relevant studies. You can add more later.

2. 02

   Identify themes

   Read your notes and look for ideas, debates or methods that keep returning. Three to five themes is a good range.

3. 03

   Fill in the grid

   For each source, write a short note in each relevant theme cell. Leave cells empty if a source does not address that theme.

4. 04

   Look across the rows

   Where do sources agree? Where do they disagree? Which cells are empty? Empty cells often point to research gaps.

5. 05

   Write your synthesis column

   For each theme, write one or two sentences in your own words summarising the overall picture. These sentences often become your topic sentences.

Write paragraphs that compare

A good literature review paragraph usually follows a simple pattern: make a claim, support it with several sources, show any disagreement or limitations, then explain what it means for your research.

• Agreement: 'Several studies suggest… (Author, year; Author, year).'
• Contrast: 'However, … argues the opposite, finding that…'
• Limitation: 'These studies mainly focus on…, which limits…'
• Building on: 'Extending this work, … shows that…'
• Relevance: 'This matters for the present study because…'

Notice that these sentences start with ideas, not author names. When every paragraph begins with 'Smith (2019) found…', it is a sign you are summarising.

Finish with the gap

The final part of your review should lead naturally to your own research question. In plain terms: given what we know and what is missing, this is what my study does and why it matters. A clear gap makes your whole dissertation feel purposeful.