Evidence-Based Policy

Over the last twenty or so years, it has become standard to require policy makers to base their recommendations on evidence. That is now uncontroversial to the point of triviality--of course, policy should be based on the facts. But are the methods that policy makers rely on to gather and analyze evidence the right ones? In Evidence-Based Policy, Nancy Cartwright and Jeremy Hardie explain that the dominant methods which are in use now--broadly speaking, methods that imitate standard practices in medicine like randomized control trials--do not work. They fail, Cartwright and Hardie contend, because they do not enhance our ability to predict if policies will be effective.