Conceptual recommendations for selecting the most appropriate knowledge synthesis method to answer research questions related to complex evidence

Objective: To compare and contrast different knowledge synthesis methods and map their specific steps through a scoping review to gain a better understanding of how to select the most appropriate knowledge synthesis method to answer research questions of complex evidence. Study design and setting: Electronic databases were searched to identify studies reporting emerging knowledge synthesis methods (e.g., Realist review) across multidisciplinary fields. Two reviewers independently selected studies and abstracted data for each article. Results: We synthesized diverse, often conflicting evidence to identify 12 unique knowledge synthesis methods and 13 analysis methods. We organized the 12 full knowledge synthesis methods according to their purpose, outputs and applicability for practice and policy, as well as general guidance on formulating the research question. To make sense of the overlap across these knowledge synthesis methods, we derived a conceptual algorithm to elucidate the process for selecting the optimal knowledge synthesis methods for particular research questions. Conclusion: These findings represent a preliminary understanding on which we will base further advancement of knowledge in this field. As part of next steps, we will convene a meeting of international leaders in the field aimed at clarifying emerging knowledge synthesis approaches.The study was funded by a Canadian Institutes of Health Research (CIHR, grant number: ​KST-116633) Knowledge Synthesis grant. ACT holds a CIHR/Drug Safety and Effectiveness Network New Investigator Award in Knowledge Synthesis, and SES holds a Tier 1 Canada Research Chair in Knowledge Translation. The authors thank Drs. Jeremy Grimshaw, David Moher, and Peter Tugwell, who provided support and expertise in knowledge synthesis methods and knowledge translation for our scoping review protocol. They also thank Drs. Vivian Welch and Tanya Horsley for their conceptualization of the scoping review; Erin Lillie, Judy Tran, and Laure Perrier for screening some citations, abstracting data, and analyzing the data; Peggy Robinson for copyediting the manuscript; and Ana Guzman for formatting the article. M.K. conceived the study, obtained funding for the study, screened citations and full-text articles, abstracted analyzed, and interpreted the data, and wrote this article. J.A. and C.S. coordinated the study, screened citations and full-text articles, abstracted data, developed the qualitative analysis, coded and analyzed data, and edited the article. S.E.S. conceived the study, obtained funding for the study, analyzed and interpreted the data, and edited the article. A.C.T. conceived the study, obtained funding for the study, screened citations and full text articles, abstracted data, analyzed and interpreted the data, and edited the article