The Alternative Vote and Coombs Rule versus First-Past-the-Post: a social choice analysis of simulated data based on English elections, 1992–2010

This paper presents a social choice analysis, using simulated data based on English general elections from 1992 through 2010, of the properties of three voting rules: First-Past-the-Post, the Alternative Vote, and the Coombs Rule. More specifically, the paper examines (1) the plurality, anti-plurality, and Condorcet status of candidates in each election and the interrelationships among these statuses, (2) the effects of strict and partial single-peakedness of voter preferences, and (3) the identity of winners, Condorcet efficiency, and the relationship between votes and seats under the three voting rules. The analysis considers only the case of three candidates and, in the manner of basic social choice theory, the set of candidates and voter preferences over them are taken to be fixed.