Cutting through the complexity to aid evidence synthesis. A response to Haddaway and Dicks

We thank Haddaway and Dicks (2017) for their interest in our recent paper: “Simplifying the selection of evidence synthesis methods to inform environmental decisions: A guide for decision makers and scientists” (Cook et al., 2017). Their response reflects a long standing tension that many conservation scientists face, between emphasising complexity and nuance, and potentially turning practitioners off; or simplifying, at the risk of constraining people's thinking. In fact, this tension has been one of the primary reasons for the development of evidence synthesis methods. The large, complex pool of literature frequently yields conflicting and contradictory results that leave end users confused and frustrated (Cochrane, 1972;Pullin and Knight, 2001). The role of evidence synthesis is to integrate that complexity and condense it to answer the essential questions of “what works?” and “under what circumstances?”. In this way, evidence synthesis can cut through the complexity and variability and provide some general guidance to decision makers.