Evidence synthesis is a general term that captures a widening universe of methodologies….Unlike these traditional narrative reviews, evidence synthesis aims to reduce biases in the process of selecting the studies that will be included in a review. Evidence synthesis uses transparent and reproducible methods to exhaustively search for information on a topic and select studies based on well-defined predetermined criteria. Depending on the type and purpose of the evidence synthesis, results from the studies that meet the criteria may be assessed for quality and bias and the results combined in a meta-analysis to reach a more complete understanding. Other evidence synthesis methods use systematic searching approaches but skip a quality assessment step and instead map, describe, or distill the existing knowledge to guide future research directions and provide decision support tools for policy-makers and practitioners. Due to the thorough nature of searching and combing through the literature, evidence synthesis typically takes longer to complete than narrative reviews do, though exceptions may exist.
Evidence synthesis can be defined as the review of what is known from existing research using systematic and explicit methods in order to clarify the evidence base and is the main focus of this journal. The research questions addressed and the methods used by such syntheses vary considerably, but they are all based on the principles of rigour and transparency. When reviews of research evidence are based on expert advice, expert panels and unsystematic methods, then the basis for the claims made by the reviews are uncertain. If reviews are not explicit and transparent in reporting their methods of review, then one cannot assess whether they have used rigorous methods that can justify the findings that they report.
Evidence synthesis is an approach to integrating findings from peer-reviewed and grey literature to summarize a substantive and diverse body of evidence. Evidence synthesis is characterized by its systematic and transparent (i.e. replicable and observable) approach to formulating questions and searching, appraising, synthesizing and packaging the body of evidence to provide a more comprehensive picture than a single study could do. This means that the methodology used (e.g. search terms, sources/databases, inclusion/exclusion criteria) is explicitly documented to leave a trail for others to replicate the search, make updates easier and assist readers to be aware of any potential bias.
The explosion of the evidence synthesis methods can lead to confusion. Before starting an evidence synthesis, it is essential to select the right approach to synthesize the evidence based on your question or topic. The next tab reviews types of evidence synthesis.
Piecing Together Systematic Reviews and Other Evidence Syntheses (ProQuest Ebook Central) by 