A KNOWLEDGE SYNTHESIS CHAPTER Prepared by : Jeremy Grimshaw

The Canadian Institute of Health Research (CIHR) defines knowledge translation as 'a dynamic and iterative process that includes the synthesis, dissemination, exchange and ethically-sound application of knowledge to improve the health of Canadians, provide more effective health services and products and strengthen the healthcare system'. This definition highlights the importance of knowledge synthesis in knowledge translation activities.(1) CIHR defines synthesis as 'the contextualization and integration of research findings of individual research studies within the larger body of knowledge on the topic. A synthesis must be reproducible and transparent in its methods, using quantitative and/or qualitative methods. It could take the form of a systematic review; follow the methods developed by The Cochrane Collaboration; result from a consensus conference or expert panel and may synthesize qualitative or quantitative results. Realist syntheses, narrative syntheses, meta-analyses, meta-syntheses and practice guidelines are all forms of synthesis.'(1) CIHR has regular RFAs for knowledge syntheses relevant to the needs of the Canadian health care system. The purpose of this chapter is to discuss the rationale for knowledge syntheses, 3 outline current approaches and methods for syntheses, and highlight available resources to aid potential applicants. Science is a cumulative process that develops iteratively; few studies by themselves are sufficiently persuasive to change practice or policy. Individual studies may be misleading due to chance or bias. Ioannidis and colleagues have undertaken a landmark series of studies exploring the evolution of basic and applied research that highlights concerns about the reliability and interpretation of individual studies. They observed that the results of the most highly cited basic science and clinical research papers published in the most prestigious journals are frequently overturned or challenged by subsequent less prominent publications.(2;3) Further they observed that the results of early publications in both basic and clinical research were often likely to report more strikingly positive or negative findings than subsequent publications.(4) Together these studies highlight the problems of focusing knowledge translation efforts on individual studies (especially early publications with striking findings) and suggest that the evidence base in any field needs to mature and be synthesized before an observer can reliably understand its implications. Reviews have always played an important role in health research and knowledge translation. Traditionally reviews were written by acknowledged experts in a field and provided little information with respect to how the expert had conducted the review, what evidence the expert considered when writing the review, or the scientific …