Working Papers
Efficiency in School Choice: Structures and Implementation Conditions for Nash Equilibria
(R&R Social Choice and Welfare)
Latest version: here
This paper examines a preference revelation game that utilizes the student-proposing deferred acceptance mechanism (DA) in the context of school choice. Our focus is on assignments that Pareto-dominate the student-optimal stable assignment, specifically investigating the structures of Nash equilibria that implement these assignments with DA (i.e., Nash equilibria that lead to these outcomes with DA). While some assignments cannot be implemented with DA, we identify a strategy profile that determines whether a given assignment is implementable when each school has a capacity of one. However, this profile cannot determine implementability when at least one school has more than one available seat. As a result, we focus on specific assignments that Pareto-dominate the student-optimal stable assignment and establish sufficient conditions on strategy profiles that can implement these assignments with DA.
Contract Terms Monotonicity in Matching Markets
(R&R Theoretical Economics)
Latest version: here
We investigate the impact of adding contract terms on stable allocations in the doctor-hospital matching market. Surprisingly, expanding term options can decrease doctors' welfare at the doctor-optimal stable allocation, even if the added terms are utilized. Our results show that withdrawing unused terms can lead to a Pareto improvement for doctors. We demonstrate the robustness of our results and examine their implementation within two preference domains commonly present in many markets: lexicographic and aligned preferences.
Efficiency and Application Fees in School Choice
Latest version: here
This paper explores the impact of application fees on student strategies within the Deferred Acceptance (DA) mechanism. We show that application fees reduce the set of Nash equilibria under DA. While they can lead to Pareto-efficient assignments, application fees may also prevent Nash equilibria that result in assignments Pareto-dominating the student-optimal stable assignment. This occurs when application fees are positive for all students at a given school.
Job Matching and Affirmative Action: The Impact of Transfer Policies
Latest version: here
Subsidies and taxes are widely used in labor markets to influence employment outcomes. This paper uses a Kelso-Crawford framework to assess how transfers affect the welfare of minority workers. We show that affirmative action policies, though well-intentioned, can unintentionally harm this group. We establish that only uniform transfers—where all workers in a group receive the same subsidy or tax across all firms—guarantee no welfare loss. Building on this insight, we explore how transfers can be designed to achieve representation goals for minority workers without reducing their welfare.
Affirmative Action with Overlapping Reserves: Equity, Fairness, and Complementarity
Latest version: here
Affirmative action policies, by establishing representation thresholds for protected groups, seek to balance fairness and equity in various assignment problems. Fairness is maintained by prioritizing individuals based on merit scores, while equity is ensured through guaranteed group representation. We focus on overlapping reserves, where individuals can belong to multiple groups, and introduce the Maximal Score and Minimum Guarantee (MSMG) choice rule, which upholds representation requirements while preserving fairness. We define the score of an assignment as the sum of the merit scores of the selected individuals. We demonstrate that the assignment produced by the MSMG choice rule achieves the highest possible score among all fair assignments that satisfy the given representation thresholds.