The idea that policy should be based on best research evidence might appear to be self-evident. But a closer analysis reveals a number of problems and paradoxes inherent in the concept of "evidence-based policymaking." The current conflict over evidence-based policymaking parallels a long-standing "paradigm war" in social research between positivist, interpretivist, and critical approaches. This article draws from this debate in order to inform the discussions over the appropriateness of evidence- based policymaking and the related question of what is the nature of policymaking. The positivist, empiricist worldview that underpins the theory and practice of evidence-based medicine (EBM) fails to address key elements of the policymaking proce...