An indifference result for social choice rules in large societies

Abstract

Social choice rules can be defined or derived by minimizing distance-based objective functions. One problem with this approach is that any social choice rule can be derived by selecting an appropriate distance function. Another problem comes from the computational difficulty of determining the solution of some social choice rules. We provide a general positive indifference result when looking at expected average distances by showing that on ‘average’ each social choice rule performs equally well with respect to a very large class of distance functions if the number of voters is large. Our result applies also to the frequently employed Kendall $\tau$, Spearman rank correlation and Spearman footrule ‘distance functions’.