The democratic virtues of randomized trials

Democratic alternation in power involves uncontrolled policy experiments. One party is elected on one policy platform that it then implements. Things may go well or badly. When another party is elected in its place, it implements a different policy. In imposing policies on the whole community, parties in effect conduct non-randomized trials without control groups. In this paper, we endorse the general idea of policy experimentation but we also argue that it can be done better by deploying in policymaking randomized controlled trials. We focus primarily on the democratic benefits of using randomized trials in policymaking and on how they can enhance the democratic legitimacy of policy. We argue that randomized trials resonate well with three key democratic principles: non-arbitrariness, revisability and public justification. Randomized trials’ contribution to non-arbitrariness and revisability is not unique; other types of evidence can advance these democratic principles as well. But through their peculiar democratic scrutability, randomized trials are well-equipped to contribute to the public justifiability of policy.