Montreal Microeconomic Theory Seminar 2017-2018
joint with the departments of economics of the universities of Montréal, Concordia and McGill as well as CIRANO
room C-6149 (U. de Montréal, Pavillon Lionel-Groulx, 3150, rue Jean-Brillant)
Organizers : Deniz Dizdar (U. of Montreal) and Sean Horan (U. of Montreal)
Abstract
A key operational issue in the school choice market is how to reassign seats that are vacated after an initial round of centralized assignment. Practical solutions to this reassignment problem must be simple to implement, truthful, efficient and fair while also alleviating costly student movement between schools. In this talk, I will propose and axiomatically justify a class of reassignment mechanisms, the Permuted Lottery Deferred Acceptance (PLDA) mechanisms. These mechanisms generalize the commonly used Deferred Acceptance (DA) school choice mechanism to a two-round setting and retain its desirable incentive, fairness and efficiency properties. School choice systems typically run Deferred Acceptance with a lottery number assigned to each student to break ties in school priorities. I will show that under natural conditions on demand, correlating the tie-breaking lotteries across rounds preserves allocative welfare, and reversing the first-round lottery order minimizes reassignment among all PLDA mechanisms. Empirical investigations based on data from NYC high school admissions support our theoretical findings.
