"This lecture addresses whether evidence-based policy and evidence-based government is possible, and whether it is more than a rhetorical device. It attempts to define evidence-based policy and considers factors other than evidence that influence policy making and policy implementation. It also considers the types of evidence used by governments and the types of research that can contribute to that evidence. Some of the mechanisms that need to be in place for evidence-based government to occur are also discussed. The lecture concludes that evidence-based government is possible and is well established in the U.K. It argues that a broader conception of evidence is used by most government than by some academics, and that a wide range of methods for gathering and appraising evidence for government is required. Some implications for the Campbell Collaboration and the academic community are suggested."