Simple Manipulations in School Choice Mechanisms

Market design mechanisms are often required to be strategy proof, ensuring that no misreporting is profitable. This, however, may be overly restrictive: Real-world participants may be unable to engage in complex misreporting. In the context of school choice, this paper proposes that mechanisms ought to be immune only to certain “simple” misreports. While no strategy-proof mechanism Pareto improves on the deferred acceptance (DA) mechanism, we find one under our weaker requirement: Kesten's (2010) efficiency adjusted DA (EADA). By extending our criterion to also prevent simple “collective” misreports, we obtain characterizations of Kesten's mechanism. These insights contribute to practical market design. (JEL C78, D47, D82, I21)