Satisfaction Approval Voting

Approval voting (AV) system is well suited to elect a single winner, which almost all the literature on AV since the 1970s has addressed. Satisfaction approval voting (SAV) works as follows when the candidates are individuals. A voter's satisfaction score is the fraction of his or her approved candidates who are elected, whether the voter is relatively discriminating or not. This chapter considers the conditions under which, in a 3-candidate election with 2 candidates to be elected, a voter's ballot might change the outcome, either by making or breaking a tie. In 2003, the Game Theory Society used AV for the first time to elect 12 new council members from a list of 24 candidates. A decision-theoretic analysis shows that all strategies under SAV, except approving of a least-preferred candidate, are undominated, so voters may rationally choose to approve of more than one candidate.