Kidney exchange: the view from Michigan

Here's a new working paper on kidney exchange, that gives thoughtful attention to the kinds of weights that might be attached to edges:

Yijiang Li, Jack Kalbfleisch, Peter Xuekun Song, Yan Zhou, and Alan Leichtman, "Optimization and Simulation of an Evolving Kidney Paired Donation (KPD) Program" (May 2011). The University of Michigan Department of Biostatistics Working Paper Series. Working Paper 90. http://www.bepress.com/umichbiostat/paper90

Abstract:
"The old concept of barter exchange has extended to the modern area of living-donor kidney transplantation, where one incompatible donor-candidate pair is matched to another pair with a complementary incompatibility, such that the donor from one pair gives an organ to a compatible candidate in the other pair and vice versa. Kidney paired donation (KPD) programs provide a unique and important platform for living incompatible donor-candidate pairs to exchange organs in order to achieve mutual benefit. We propose a novel approach to organizing kidney exchanges in an evolving KPD program with advantages, including (i) it allows for a more exible utility-based evaluation of potential kidney transplants; (ii) it takes into consideration stochastic features in managing a KPD program; and (iii) it exploits possible alternative exchanges when the originally planned allocation cannot be fully executed. Another primary contribution of this work is rooted in the development of a comprehensive microsimulation system for simulating and studying various aspects of an evolving KPD program. Various allocations can be obtained using integer programming (IP) techniques and microsimulation models can allow tracking of the evolving KPD over a series of match runs to evaluate different allocation strategies. Simulation studies are provided to illustrate the proposed method."