Library Guides: Systematic Style Reviews: Types of reviews

Review type	Description & purpose	Literature search	Quality appraisal	Analysis methods	Recommended timeframe*	Reviewers required	Limitations
Systematic	Comprehensive evidence synthesis, considered the gold standard review with a focus on high level evidence (often randomised controlled trials, but this depends on the question type). May be useful for clinical decision-making, determining best practice The Cochrane Collaboration is considered the eminent organisation for systematic reviews. Note: not all systematic reviews include meta-analyses	Comprehensive	Included - this may determine inclusion/exclusion	What is known: recommendations for practice or what remains unknown: uncertainty around findings, recommendations for future research	9-12+ months	at least 2	Narrow scope of question limits insights on broader topic.
Scoping	Exploratory review. May assist with determining areas for new research or the usefulness of a future systematic review	Completeness determined by time/scope restraints	No formal quality assessment	Characterises quantity and quality of literature perhaps by study design and other key features	6-12+ months	at least 2	Difficulty in establishing boundaries due to wide scope. Difficult to interpret results due to lack of quality assessment. Does not synthesise results.
Rapid	Rapid evidence synthesis. May assist with determining best practice.	Comprehensive Completeness determined by time/scope restraints?	Included - this may determine inclusion/exclusion	What is known: recommendations for practice or what remains unknown: uncertainty around findings, recommendations for future research	1 - 6 months	at least 1	Search not as comprehensive. Limited time frame may introduce bias. Only one reviewer may cause possible non-blinded appraisal and selection. Omitting components of the review process may cause limitations and potential biases. Interpretation of the findings may be limited or cautious.
Integrative	Aggregates and evaluates both experimental and non-experimental data to determine best practice. May assist where diverse methodologies are required to answer a question, or where empirical evidence may not exist.	Comprehensive	Included - this may determine inclusion/exclusion	What is known: recommendations for practice or what remains unknown: uncertainty around findings, recommendations for future research	12+ months	at least 2-3
Umbrella	Systematic review of other systematic reviews Usually used for best practice for treatment.		Included - this may determine inclusion/exclusion	What is known: recommendations for practice or what remains unknown: uncertainty around findings, recommendations for future research	9-12+ months	at least 2	Must include the re-synthesis of data. Only includes systematic reviews and meta-analyses, does not include other study types. Requires a systematic review expert to critically appraise systematic reviews.
Meta-analysis	Strictly speaking not a review, but is usually developed from or within a systematic review. Determines the effectiveness of interventions by applying statistical analysis to the combined results of individual studies.	Comprehensive	Included - this may determine inclusion/exclusion	What is known: recommendations for practice or what remains unknown: uncertainty around findings, recommendations for future research	12 - 24 months	at least 2-3	Requires specialist statistical expertise and software. Assumes that all interventions are equally applicable to all populations and contexts of the studies included. May introduce study selection bias.
Meta-synthesis	An interpretive synthesis of qualitative data which provides new insights into the research.	Comprehensive	Included - this may determine inclusion/exclusion	What is known: recommendations for practice or what remains unknown: uncertainty around findings, recommendations for future research	NA	NA	Only appropriate for high-quality qualitative studies Selection of review type may not be possible until studies selected. Requires significant methodological skill and experience with qualitative methods. May take time to engage with the evidence and develop theory. Requires further interpretation by policy makers and practitioners.
Traditional / Narrative	Increase self-knowledge of an area, provide a broad overview or identify gaps in the literature. May be used as background for research.	May or may not be comprehensive	May or may not include	May be chronological, conceptual, thematic etc.	1 week - 1 month	1	No data about author's purpose or agenda. No explicit analysis of data. Possible study selection bias.

*timeframe may vary from this guide, depending on the number of eligible articles included in the review and other demands on the reviewers' time.

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Types of Reviews - What kind of review do we need
Produced by the National Collaborating Centre for Methods and Tools, which is funded by the Public Health Agency of Canada and affiliated with McMaster University.