Short trading cycles: Paired kidney exchange with strict ordinal preferences
Abstract 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.
Math. Soc. Sci.