arXiv subjects

Peter Troyan

Publications and source records attributed to Peter Troyan.

3 recordsLinked to original sources

arXiv2023

Rankings-Dependent Preferences: A Real Goods Matching Experiment

We investigate whether preferences for objects received via a matching mechanism are influenced by how highly agents rank them in their reported rank order list. We hypothesize that all else equal, agents receive greater utility for the same object when they rank it higher. The addition of rankings-dependent utility implies that it may not be a dominant strategy to submit truthful preferences to a strategyproof mechanism, and that non-strategyproof mechanisms that give more agents objects they \emph{report} as higher ranked may increase market welfare. We test these hypotheses with a matching experiment in a strategyproof mechanism, the random serial dictatorship, and a non-strategyproof mechanism, the Boston mechanism. A novel feature of our experimental design is that the objects allocated in the matching markets are real goods, which allows us to directly measure rankings-dependence by eliciting values for goods both inside and outside of the mechanism. The experimental results are mixed, with stronger evidence for rankings-dependence in the RSD treatment than the Boston treatment. We find no differences between the two mechanisms for the rates of truth-telling and the final welfare.

econ.GN↗

arXiv2022

Non-Obvious Manipulability of the Rank-Minimizing Mechanism

In assignment problems, the rank distribution of assigned objects is often used to evaluate match quality. Rank-minimizing (RM) mechanisms directly optimize for average rank. While appealing, a drawback is RM mechanisms are not strategyproof. This paper investigates whether RM satisfies the weaker incentive notion of non-obvious manipulability (NOM, Troyan and Morrill, 2020). I show any RM mechanism with full support - placing positive probability on all rank-minimizing allocations - is NOM. In particular, uniform randomization satisfies this condition. Without full support, whether an RM mechanism is NOM or not depends on the details of the selection rule.

econ.TH↗

arXiv2022

Desirable Rankings

We study the problem of aggregating individual preferences over alternatives into a collective ranking. A distinctive feature of our setting is that agents are matched to alternatives. Applications include rankings of colleges or academic journals. The foundation of our approach is that alternatives agents desire -- that is, those they rank above their match -- should also be ranked higher socially. We introduce axioms to formalize this idea and call rankings that satisfy them desirable. We develop an algorithm to construct desirable rankings and prove that, as the market becomes large, desirable rankings converge to the true underlying ranking of the alternatives by quality. We support this convergence result through simulations and demonstrate the practical usefulness of our approach by ranking Chilean medical programs with data from their centralized admission system. Finally, we compare performance and show that our approach outperforms two benchmarks: revealed preference rankings and Borda counts.

econ.TH↗