Robust participation incentives in dynamic kidney exchange

Robustness to plausible distributions of outcomes helps rationalize straightforward participation incentives for Compatible patient–donor Pairs in dynamic kidney exchange programs. The CP faces ambiguity on the distribution of outcomes in every matching round and evaluates participation conditions -minimum guaranteed quality and committed number of rounds before fallback- according to every plausible distribution. When the decay of the donor’s organ quality between rounds is negligible, the ex-ante and ex-post individually rational socially optimal contract involves a minimum guarantee exactly equal to the fallback option and an unlimited, self-enforced stay at the pool. The model also easily explains that no contract can attract a CP with sufficiently high reservation value to the exchange pool. • Participation under ambiguity: Compatible patient–donor pairs evaluate participation rules (minimum guaranteed quality and waiting rounds) under uncertain outcome distributions, which can still support participation in dynamic kidney exchange. • Optimal contract: If donor organ quality does not significantly decay across rounds, the optimal contract guarantees a minimum equal to the fallback option and allows an unlimited, self-enforced stay in the pool. • Participation limits: Pairs with sufficiently high reservation values cannot be attracted to the exchange pool by any feasible contract.