Social Welfare Maximization in Approval-Based Committee Voting under Uncertainty

Abstract: Approval voting is widely used for making multi-winner voting decisions. The canonical rule (also called Approval Voting) used in the setting aims to maximize social welfare by selecting candidates with the highest number of approvals. We revisit approval-based multi-winner voting in scenarios where the information regarding the voters' preferences is uncertain. We present several algorithmic results for problems related to social welfare maximization under uncertainty, including computing an outcome that is social welfare maximizing with the highest probability, computing the social welfare probability distribution of a given outcome, computing the probability that a given outcome is social welfare maximizing, and understanding how robust an outcome is with respect to social welfare maximizing.