The unavailable candidate model: a decision-theoretic view of social choice

One of the fundamental problems in the theory of social choice is aggregating the rankings of a set of agents (or voters) into a consensus ranking. Rank aggregation has found application in a variety of computational contexts. However, the goal of constructing a consensus ranking rather than, say, a single outcome (or winner) is often left unjustified, calling into question the suitability of classical rank aggregation methods. We introduce a novel model which offers a decision-theoretic motivation for constructing a consensus ranking. Our unavailable candidate model assumes that a consensus choice must be made, but that candidates may become unavailable after voters express their preferences. Roughly speaking, a consensus ranking serves as a compact, easily communicable representation of a decision policy that can be used to make choices in the face of uncertain candidate availability. We use this model to define a principled aggregation method that minimizes expected voter dissati...

• Type: Conference
• Year: 2010
• Where: SIGECOM
• Authors: Tyler Lu, Craig Boutilier
• Keywords: Consensus Ranking, ECommerce, Rank Aggregation, SIGECOM 2010, Unavailable Candidate Model