School Choice with Unequal Outside Options

Students with identical valuations for public schools but unequal outside options have different opportunity costs of revealing their preferences. Consequently, manipulable mechanisms need not resolve conflicting preferences in a Pareto-improving manner. We show that when they do not, welfare improvements for students with outside options come at the expense of students without outside options. This result strengthens the argument that strategyproof mechanisms “level the playing field.” Our model predicts that students without outside options are more likely to strategize, consistent with recent findings in empirical studies of education markets.