Literature Review vs Systematic Review vs Meta-Analysis, with Real Data

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Below, we compare the three in plain language, explain how each is conducted, and use live data to show how often each appears in the publications of PhD researchers on ScholarsColab, and how often they are cited.

Literature review vs systematic review vs meta-analysis at a glance

Every meta-analysis should rest on a systematic search, but not every systematic review includes a meta-analysis: if the studies are too different to combine, the review summarises them in words and tables instead.

Example: reviews in ScholarsColab’s data

To explain the three kinds of review, we look at the reviews published by PhD researchers on ScholarsColab. Our data: 41,792 papers, mostly published between 1998 and 2026, by 967 ScholarsColab mentors (data updated 15 October 2026).

Step 1
Spot the type from the title. Titles with “systematic review” or “meta-analysis” follow the strict method; titles with “review”, “overview” or “recent advances” are usually literature (narrative) reviews. Here are real systematic reviews and meta-analyses by our mentors:

Step 2
See why reviews matter: they are cited a lot. Each bar shows the typical number of citations for one type of paper:

Among 22,045 papers published between 2010 and 2022, review articles received a median of 13 citations, compared with 6 for original research papers: about 2.2× as many. Systematic reviews and meta-analyses alone reached a median of 30 citations, about 5× that of original research. Reviews are cited often because one review saves other researchers from reading dozens of studies.

Step 3
Notice the trend. 301 of the 41,792 papers in our data (0.7%) show this in their title: systematic review / meta-analysis. It is most common in Medicine & health, where 2.5% of papers show it. Its share of papers rose from 0.1% in 2012–2013 to 1.1% in 2024–2025.

Systematic reviews are growing because funders, guideline makers and journals increasingly want answers based on all the evidence, not a selection of it.

How each type of review is conducted

Literature review

Identify the key themes of a topic, search the main databases and reference lists, read and critically evaluate the important studies, and organise them around themes, debates and gaps. In a thesis, the literature review shows where your study fits and why it is needed.

Systematic review

1. Frame a focused question, often using a structure such as PICO (population, intervention, comparison, outcome).
2. Register a protocol describing the planned methods, for example on PROSPERO.
3. Search several databases with a documented search strategy.
4. Screen studies against pre-set criteria, ideally with two independent reviewers.
5. Extract data and assess each study’s risk of bias.
6. Synthesise the findings and report them following PRISMA guidelines.

Meta-analysis

After a systematic review, convert each study’s result to a common effect size, combine them with a fixed-effect or random-effects model, check how much the studies disagree (heterogeneity), and test for publication bias, for example with a funnel plot.

Which one does your research need?

Common mistakes reviewers point out

• Calling a narrative review “systematic” without a documented search and selection process.
• Searching only one database, which misses relevant studies.
• Combining studies that are too different in a meta-analysis.
• Skipping the risk-of-bias assessment, so weak and strong studies count equally.
• Listing studies one by one instead of synthesising what they show together.

Frequently asked questions

Use this data in your own work

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