Handbook on Approval Voting

Abstract

Approval voting (AV) is a voting procedure in which voters can vote for, or approve of, as many candidates as they like in multicandidate elections (i.e., those with more than two candidates). Each candidate approved of receives one vote, and the candidate with the most votes wins. This chapter reviews the theoretical and empirical literature on the properties of AV when voters are strategic. The literature analyzes voting situations from a game-theoretic perspective, where voters choose their approval sets strategically in order to maximize their utility. The chapter presents the main results of this literature and discusses the implications of the assumptions that voters use undominated strategies and that voters behave sincerely. The chapter also discusses the implications of the different types of equilibria that can arise under Approval Voting. In particular, it examines the possibility of using more powerful tools than Nash equilibrium in order to either predict the outcome of a voting game or to narrow down the set of possible outcomes. The chapter concludes by discussing the implications of the theoretical results for real elections. – AI-generated abstract