Tuomas Sandholm

Talk Title:
Modern Organ Exchanges: Market Designs, Algorithms, and Opportunities

Talk Abstract:
I will share experiences from working on organ exchanges for the last 18 years, ranging from market designs to new optimization algorithms to large-scale fielding of the techniques and even to computational policy optimization. Originally in kidney exchange, patients with kidney disease obtained compatible donors by swapping their own willing but incompatible donors. I will discuss many modern generalizations of this basic idea. For one, I will discuss never-ending altruist donor chains that have become the main modality of kidney exchanges worldwide and have led to over 10,000 life-saving transplants. Since 2010, our algorithms have been running the national kidney exchange for United Network for Organ Sharing, which has grown to include 80% of the transplant centers in the US. Our algorithms autonomously make the transplant plan each week for that exchange, and have been used by two private exchanges before that. I will summarize the state of the art in algorithms for the batch problem, approaches for the dynamic problem where pairs and altruists arrive and depart, techniques that find the highest-expected-quality solution under the real challenge of unforeseen pre-transplant incompatibilities, algorithms for pre-match compatibility testing, and approaches for striking fairness-efficiency tradeoffs. I will describe the FUTUREMATCH framework that combines these elements and uses data and supercomputing to optimize the policy from high-level human value judgments. The approaches therein may be able to serve as ways of designing policies for many kinds of complex real-world AI systems. I will also discuss the idea of liver lobe exchanges and cross-organ exchanges, and how they have started to emerge for real.