Although this guide will focus on systematic and scoping reviews, we wanted to provide you with an introduction to a variety of reviews in case one of them fits your needs better. The methods for all reviews have a lot in common. It is in the purpose and the analysis where most differences arise.
| Review Type | Purpose | Analysis |
| Narrative Review | Provide an overview of relevant literature. This is the review type most commonly seen in the "literature review" section of a published study. Does not require a comprehensive search of the literature. | Typically thematic but may be chronological. Does not usually include a formal quality appraisal. |
| Scoping Review | Provide a description of the scope of available literature on a topic. The topics can be quite broad. Usually involves a comprehensive search and includes all types of relevant records, i.e. grey literature. May be used to identify research gaps or potential topics for future systematic reviews. | Narrative and tabular analysis, typically highlighting key features of the available literature. Does not require quality appraisal. |
| Systematic Review | Synthesize homogenous studies in order to provide a summary of evidence and recommendations for practice. Requires a comprehensive search, often limited by study design. | Narrative and tabular analysis, focusing on outcomes data. Requires quality appraisal which may be used as inclusion/exclusion criterion. |
| Meta-analysis | Combine and analyze the results from homogenous studies in order to produce a more robust conclusion of effect. Requires a comprehensive search, typically limited by study design type. | Tabular with narrative commentary. Requires quality appraisal which may be used as inclusion/exclusion criterion. |
| Integrative Review | Gather and synthesize evidence relevant to a clearly defined problem. Should include a comprehensive search of all relevant types of literature. | Narrative and tabular analysis. Quality appraisal is recommended. |
| Rapid Review | A variation of the systematic review to provide a timely synthesis of evidence to aid in decision-making, often on urgent or high priority issues. Comprehensiveness of the search is determined by time limitations. | Narrative and tabular analysis, focusing on outcomes data. Quality appraisal may be abbreviated due to time limitations. |
| Empty Review | To highlight a gap in the literature. An empty review is one where no literature matches the defined criteria in the research question. In other words, your search comes up empty. A comprehensive search of all available research is an absolute must for an empty review. | No analysis, unless there is evidence as to why there is a gap in the evidence. Discussion should focus on recommendations and guidance for future research. |
| Umbrella Review | A review of systematic reviews and meta-analyses. Topics are typically broader than a single systematic review to address multiple approaches to a condition or problem. Most frequently used to compare interventions or exposures. A comprehensive search for all relevant systematic reviews and meta-analyses is required. | Tabular with commentary. Focus on outcomes data to highlight what is known and potentially make recommendations for practice. |
(Arksey & O'Malley, 2005; Belbasis et al., 2022; Field & Gillett, 2010; Garritty et al., 2024; Grant & Booth, 2009; Slyer, 2016; Whittemore & Knafl, 2005)
Need more help deciding which review is right for you? These articles might help you decide
When possible, these links are to guidelines endorsed by organizations. When that is not possible, the links are to documents written by helpful academics with advice on conducting review.
Scoping Reviews
Systematic Reviews
Meta-Analyses
Integrative Reviews
Rapid Reviews
Empty Reviews
Umbrella Reviews
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Aside from the usual ethical considerations authors need to have, such as conflict of interest, there are a few that are particular to reviews.
Avoiding Bias
Some general principles to follow in order to avoid bias while conducting your review.
Search Strategy
Your search strategy should be rigorous and transparent with all information about the search disclosed to the point that someone could easily recreate your search. To that end, here's what to do
Inclusion/Exclusion Criteria
Since your inclusion/exclusion criteria determine which records make it into your review. You want to be very clear about these. If someone were to try to recreate your review, they would need to know exactly how you made your decisions. Be precise when reporting your inclusion/exclusion and include operational definitions when appropriate.
Acknowledging Limitations
Make sure your readers know you are aware of any limitations that may impact the outcomes of your review.
