Short trading cycles: Paired kidney exchange with strict ordinal preferences
Mathematical Social Sciences | Elsevier BV | Published : 2020
I study kidney exchange with strict ordinal preferences and with constraints on the lengths of the exchange cycles. Efficient deterministic mechanisms have poor fairness properties in this environment. Instead, I propose an individually rational, ordinally efficient and anonymous random mechanism for two-way kidney exchange based on Bogomolnaia and Moulin’s (2001) Probabilistic Serial mechanism. Individual rationality incentivizes patient-donor pairs who are compatible with each other to participate in the exchange, thus increasing the overall transplantation rate. Finally, individual rationality, ex-post efficiency and weak strategyproofness are incompatible for any mechanism.
Awarded by National Science Foundation (USA)
This paper was previously circulated as the first half of a longer manuscript with the same title. I am particularly grateful to Haluk Ergin, and the two anonymous reviewers, as well as to David Ahn, Satoshi Fukuda, Yuichiro Kamada, Fuhito Kojima, Maciej Kotowski, C. Matthew Leister, Simon Loertscher, Antonio Miralles, Michele Muller-Itten, Chris Shannon, Yong Song, and Utku Unver. I am grateful to Laura Waring for excellent research assistance. The work was partly supported by National Science Foundation (USA grant SES-1227707.