|Systematic Review||Exhaustive and comprehensive search. Appraises and synthesizes research. Results of systematic reviews include what is known, recommendations for future research, what remains unknown, and any uncertainty during review.|
|Meta-Analysis||Statistically combines the outcomes of quantitative studies to measure effect of the results. Exhaustive and comprehensive search.|
|Rapid Review||More time-sensitive than other review types. Typically takes 1-6 months to complete. Analyzes the quantities of literature and general direction of results. Less rigorous compared to other review types with limited interpretation of findings.|
|Mixed Methods||When a combination of methods (such as qualitative and quantitative) are used to review a set of studies. This method combines the findings of both types of reviews in order to identify research gaps. Typically take 12-18 months to complete.|
|Umbrella Review||Compilation of evidence from many reviews and highlights interventions. Assesses quality of reviews and provides recommendations, lists what remains unknown, as well as recommendations for future research.|
Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009 Jun;26(2):91-108. PMID: 19490148.
"One of the most common errors in understanding systematic reviews is the perception that they are interchangeable with meta-analyses. “Systematic review” is the overarching term for studies that collate available evidence related to a directed clinical question.2,4 A meta-analysis is a review in which statistical methods are employed to collate the numeric data from the primary studies. For various reasons, not all systematic reviews can combine the available data to generate summary numeric results; however, all systematic reviews should employ stringent methods to summarize the available research."