Subject and Research Guides: Systematic Reviews: Overview

What are Systematic Reviews?

Systematic Reviews (SRs) aim to find and evaluate all studies, published and unpublished, relevant to a research question. They use systematic methods to minimise bias and they also use transparent methods that allow for replication and verification.

Key characteristics are:

a clearly stated research question with pre-defined eligibility criteria for studies
an explicit, reproducible methodology
a comprehensive search strategy that attempts to identify all studies that would meet the eligibility criteria
an appraisal of the validity of the findings of the included studies, for example through the assessment of risk of bias
a synthesis and interpretation of the findings of the included studies (Cochrane Handbook for Systematic Reviews of Interventions, 2008, p. 6)

Meta-analysis is a systematic review that uses quantitative methods to synthesise and summarise the results.

Comparison of Systematic Reviews and Literature Reviews

The table is taken from an article reviewing fourteen types of reviews:

	Systematic Review	Literature Review
Description	Seeks to systematically search for, appraise and synthesise research evidence, often adhering to guidelines on the conduct of a review	Generic term: published materials that provide examination of recent or current literature. Can cover wide range of subjects at various levels of comprehensiveness. May include research findings
Search	Aims for exhaustive, comprehensive searching	May or may not include comprehensive searching
Appraisal	Quality assessment may determine inclusion/exclusion	May or may not include quality assessment
Synthesis	Typically narrative, with tabular accompaniment	Typically narrative
Analysis	What is known; recommendations for practice. What remains unknown; uncertainty around findings, recommendations for future research	Analysis may be chronological, conceptual, thematic, etc

A typology of reviews: an analysis of 14 review types and associated methodologies. Table 1:(Grant and Booth, 2009): Table 1: Main review types characterized by methods used.

Other Review Types

A Critical Review aims:

to demonstrate you have extensively researched the literature and critically evaluated its quality. It goes beyond mere description to include a degree of analysis and conceptual innovation and typically results in an hypothesis or model
to identify the most significant items in the field

A Scoping Review aims:

to identify the nature and extent of research evidence (usually including ongoing research) on a topic or field of interest
to offer a preliminary assessment of the available research literature

This review type is about compiling evidence from multiple reviews that offer different findings for dealing with a condition or problem. The evidence is summarised in one document.

A Literature Review aims:

to identify the key authors/researchers in an area of study and provide information on a particular topic demonstrating an understanding of the field of study and an awareness of the main issues in the field
to discuss the strengths and weaknesses of the existing research in the field
to highlight knowledge gaps in a field of study
to demonstrate how current ideas in the field fit with or support your work (or not) and whether you agree or disagree with these ideas.

Literature Review Guide

Rapid reviews are a type of knowledge synthesis in which systematic review methods are streamlined and processes are accelerated to complete the review more quickly.