Syntheses = systematic reviews or meta-analyses of the literature. According to the Centre for Evidence-Based Medicine in Toronto: "Systematic reviews focus on peer-reviewed publications about a specific health problem and use rigorous, standardized methods for selecting and assessing articles. A systematic review may or may not include a meta-analysis, which is a quantitative summary of the results."3
Meta-analyses are often considered a type of systematic review where the quantitative data are combined and examined across all single studies included in the study. There are specific and detailed guidelines set by the premier publisher of systematic reviews, the Cochrane Collaboration
, on how to appropriately conduct a systematic review of the literature.
As Syntheses systematically search and critically analyze the evidence found across multiple studies, they contain a higher level of evidence than a single study or a commentary of a single study (synopses of studies). With this tier, critical appraisal of the validity and evidence in all the studies contained in a systematic review has already been done for you. Just remember that systematic reviews typically look at a very narrow subset of a particular topic and are not overarching summaries of the literature (we will be looking at this in Summaries).
Types of Reviews: Systematic, Narrative, and Litearture Reviews
Systematic reviews are often confused with narrative reviews (review articles) or literature reviews. Narrative reviews generally examine the literature from the author's perspective and include author commentary with no criteria for searching and including literature. Literature reviews usually try to identify trends across a subject, do not have a reproducible search or methodology, and do not attempt to appraise the validity of the articles.
Key Resources for Locating Systematic Reviews
Centre for Evidence-Based Medicine. Glossary. https://www.cebm.net/2014/06/glossary/. Accessed March 27, 2018.
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