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Matching Markets - Behavioral Issues and New Theoretical Approaches

Paper Session

Sunday, Jan. 6, 2019 8:00 AM - 10:00 AM

Atlanta Marriott Marquis, L507
Hosted By: Econometric Society
  • Chair: Jacob Leshno, Columbia University

Strategic ‘Mistakes’: Implications for Market Design Research

Georgy Artemov
,
University of Melbourne
Yeon-Koo Che
,
Columbia University
Yinghua He
,
Rice University

Abstract

Using a rich data set on Australian college admissions, we show that even in strategically straightforward situations, a non-negligible fraction of applicants adopt strategies that are unambiguously dominated; however, the majority of these ‘mistakes’ are payoff irrelevant. We then propose a new equilibrium solution concept that allows for mistakes. Applying it to a strategy-proof mechanism in which colleges strictly rank applicants, we show that equilibrium strategies need not be truth-telling, but that every equilibrium outcome is asymptotically stable. Our Monte Carlo simulations illustrate the differences between the empirical methods based on truth-telling or outcome stability, revealing that the latter is more robust to potential mistakes. Taken together, our results suggest that strategy-proof mechanisms perform reasonably well in real life, although applicants’ mistakes should be carefully taken into account in empirical analysis.

The Cutoff Structure of Top Trading Cycles in School Choice

Jacob Leshno
,
Columbia University
Irene Lo
,
Columbia University

Abstract

This paper develops a tractable theoretical framework for the Top Trading Cycles (TTC) mechanism for school choice that allows quantifying welfare and optimizing policy decisions. We compute welfare for TTC and Deferred Acceptance (DA) under different priority structures, and find that the choice of priorities can have larger welfare implications than the choice of mechanism. We solve for the welfare-maximizing distributions of school quality for parametrized economies, and find that optimal investment decisions can be very different under TTC and DA.

Our framework relies on a novel characterization of the TTC assignment in terms of a cutoff for each pair of schools. These cutoffs parallel prices in competitive equilibrium, with students' priorities serving the role of endowments. We show that these cutoffs can be computed directly from the distribution of preferences and priorities in a continuum model, and derive closed-form solutions and comparative statics for parameterized settings. The TTC cutoffs clarify the role of priorities in determining the TTC assignment, but also demonstrate that TTC is more complicated than DA.

Complementary Inputs and Stability in Large Trading Networks

Ravi Jagadeesan
,
Harvard University

Abstract

This paper studies a model of large trading networks with bilateral contracts. Contracts capture exchange, production, and prices, as well as frictions, such as market incompleteness, price regulation, and taxes. In my setting, a stable outcome exists in any acyclic network, as long as firms regard sales as substitutes and standard continuity and convexity conditions are satisfied. Thus, complementarities between inputs do not preclude the existence of stable outcomes in large supply chains, unlike in discrete markets. Additional results explain what kinds of equilibria are guaranteed to exist when substitutability in the sale direction and acyclicity are relaxed.

Obvious Dominance and Random Priority

Marek Pycia
,
University of California-Los Angeles
Peter Troyan
,
University of Virginia

Abstract

We construct the full class of obviously strategy-proof mechanisms in environments without transfers as the class of clinch-or-pass games we call millipede games. Some millipede games are indeed simple and widely used in practice, while others may be complex, requiring agents to perform lengthy backward induction, and are rarely observed. We introduce a natural strengthening of obvious strategy-proofness called strong obvious strategy-proofness, which eliminates some of the more complex millipede games. We use our definition to characterize the well-known Random Priority mechanism as the unique mechanism that is efficient, fair, and simple to play, thereby explaining its popularity in practical applications.
Discussant(s)
Allan Hernandez Chanto
,
Queensland University
Ran Shorrer
,
Pennsylvania State University
Alexandru Nichifor
,
University of Melbourne
Shengwu Li
,
Harvard University
JEL Classifications
  • D4 - Market Structure, Pricing, and Design
  • D9 - Micro-Based Behavioral Economics