In short: A literature (narrative) review gives an expert overview of a topic. A systematic review uses a pre-defined, reproducible method to find and appraise all relevant studies. A meta-analysis statistically combines those studies' results — and is often, but not always, part of a systematic review.
Why the distinction matters
These terms are frequently confused, yet they describe different article types with different methods, standards and levels of evidence. Naming your review correctly — and following the right method — is essential for a smooth review process.
Literature (narrative) review
A narrative review summarises and interprets the literature on a topic based on the authors' selection and expertise. It is valuable for giving context, synthesising ideas and identifying gaps. Its limitation is that the selection of studies is not exhaustive or fully reproducible, so it is more prone to selection bias.
Systematic review
A systematic review answers a focused question using an explicit, reproducible method:
- A pre-registered protocol (for example in PROSPERO for health reviews);
- A documented search strategy across multiple databases;
- Clear inclusion and exclusion criteria;
- Formal quality/risk-of-bias appraisal;
- Transparent reporting, typically following PRISMA.
Because the method is explicit, another team could repeat it and reach the same set of included studies.
Meta-analysis
A meta-analysis is a statistical method that pools the quantitative results of multiple studies to produce a combined estimate — often shown as a forest plot. It increases statistical power and precision, but its validity depends entirely on the quality and comparability of the included studies. A meta-analysis is usually conducted within a systematic review.
How they relate
Literature review → an expert overview. Systematic review → a reproducible method to find and appraise the evidence. Meta-analysis → the statistical synthesis of that evidence, often inside a systematic review.
Key takeaways
- A narrative review is an expert overview; a systematic review is a reproducible method.
- A meta-analysis statistically combines results and is often part of a systematic review.
- Systematic reviews use a protocol, explicit search, appraisal and PRISMA reporting.
- Choose the type that matches your question and follow its standards.