Evidence (or knowledge) synthesis refers to any method of identifying, selecting, and combining results from multiple studies. According to the Cochrane Collaboration, evidence synthesis "involves combining information from multiple studies investigating the same topic to comprehensively understand their findings" (Cochrane, 2023).
Evidence synthesis offers several key advantages:
- Reduces information overload: With the rapid pace of medical research, keeping up with the latest studies can be overwhelming. Evidence synthesis helps by gathering all the available information and presenting it in a clear, concise format, ensuring that only high-quality studies are included in the review.
- Strengthens findings by combining small studies: Small studies often lack sufficient data to draw definitive conclusions. However, when these studies are combined with others, they can provide a more comprehensive and compelling picture.
- Explains inconsistencies in research: Research on healthcare and health effects (and other topics) can often seem contradictory. Evidence synthesis helps make sense of the discrepancies by reviewing the entire body of research, excluding poorly designed or irrelevant studies, and accounting for differences in study design or random variations. This process provides a clearer, more reliable understanding of the evidence on a particular issue.
(Sullivan, 2017).
This brief video from Cochrane gives a good overview of the importance of evidence synthesis: