Wednesday, December 9, 2009

Course allocation at HBS

Some of the gems of the market design literature involve the careful analysis of existing institutions for allocating scarce goods, to understand the good and bad properties of those mechanisms, and the incentives they give to participants.

The latest example analyzes the way second year MBA courses at the Harvard Business School are assigned.

The Multi-unit Assignment Problem: Theory and Evidence from Course Allocation at Harvard by Eric Budish and Estelle Cantillon

Abstract: "This paper uses data consisting of agents. strategically reported preferences and their underlying true preferences to study strategic behavior in the course allocation mechanism used at Harvard Business School. We show that the mechanism is manipulable in theory, manipulated by students in practice, and that these manipulations cause meaningful welfare losses. However, we also find that ex-ante welfare is higher than under the Random Serial Dictatorship (RSD), which is the only known mechanism that is anonymous, strategyproof and ex-post efficient. We trace the poor ex-ante performance of RSD to a phenomenon, "callousness", specific to multi-unit assignment and unrelated to risk attitudes. We draw lessons for the design of multi-unit assignment mechanisms and for market design more broadly."

A related paper is Budish's proposal for an alternative mechanism: The Combinatorial Assignment Problem: Approximate Competitive Equilibrium from Equal Incomes.
(And here's my earlier post on an early version of that paper.)

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