- Whither Social Choice? (slides)
Marc Fleurbaey (Princeton University and Institute for Global Studies, Paris)
Abstract: Five problems have been bothering social choice theorists and still cast a shadow on applied welfare economics and cost-benefit analysis: 1) Arrow's impossibility; 2) Sen's Liberal Paradox; 3) Harsanyi's utilitarian theorem; 4) Parfit's "repugnant conclusion"; 5) Maximin theorems in fair allocation. These problems reveal deep conceptual issues and point to the need for a map of the tensions between the ethical values that people of good will would like to jointly promote in social and economic policies. In this lecture, I will revisit our understanding of how hard or soft the difficulties are, and argue that we should explore the construction of a normative theory for (past, present and future) humanity as a whole.
- Learning and Efficiency in Games (slides)
Éva Tardos (Cornell University)
Selfish behavior can often lead to suboptimal outcomes for all participants. Over the last decade we have developed good understanding on how to quantify the impact of strategic user behavior on overall performance via studying stable Nash equilibria of the games. In this talk we will consider the quality of outcomes when players use a form of learning that helps them to adapt to the environment, and will discuss the speed at which learning dynamic approaches the Nash equilibrium welfare. We will also consider games with dynamically changing populations, and where participants have to adapt to the dynamic environment. We show that in large classes of games, learning players ensure outcome with high social welfare, even under very frequent changes.
- Multi-Donor Organ Exchange (slides)
Utku Ünver (Boston College)
Abstract: Owing to the worldwide shortage of deceased donor organs for transplantation, living donations became a significant source of transplant organs. However, not all willing donors can donate to their intended recipients because of medical incompatibilities. These incompatibilities can be overcome by an exchange of donors between patients. Such exchanges have become widespread in the last decade for kidneys with the introduction of optimization and market design techniques to kidney exchange. A small but growing number of liver exchanges has also been conducted. Over the last two decades a number of transplantation procedures emerged where organs from multiple living donors are transplanted to a single patient. Prominent examples include dual-graft liver transplantation, lobar lung transplantation, and simultaneous liver-kidney transplantation. Exchange, however, is neither practiced nor introduced in this context. We introduce multi-donor organ exchange as a novel transplantation modality, provide a model for its analysis, and introduce optimal exchange mechanisms under various logistical constraints. Our simulations suggest that living-donor transplants can be significantly increased through multi-donor organ exchanges.