Fair Voting Methods

Decisions are everywhere--from a group's choice of pizza to a decision on a family vacation to the elections of political leaders. Central to the functioning of our organizations is the belief that these decisions reflect the wishes of voters. Yet most voting rules are unreliable and can lead to unfair outcomes. And, while a large body of academic literature describes the flaws and limitations of standard voting methods, little is known about why they occur.

In Fair Voting Methods, Donald G. Saari explores the difficulties that have plagued social choice theory for over seventy-five years. Focusing on ranked choice voting and group decision-making, Saari expands on Arrow's impossibility theorem and presents a more precise statement: all standard voting rules either fail to always rank the candidates to determine who is preferred to whom, or the voting outcomes can result in inferior choices that are not what the voters wanted. Saari then identifies and resolves the structures that negatively impact voting systems. While Arrow's seminal result asserted that the problems of standard voting systems are unavoidable, Saari makes a bold and compelling case that there are indeed usable fair voting methods. He introduces one such method that achieves Arrow's objectives of always ranking candidates with outcomes that reflect voters' intent. The book concludes by applying insights from voting theory into other topics where parts are also assembled into wholes, including judgement aggregation, corporate structures, crime prevention, the US Electoral College, and standard scientific procedures.