How robust is majority voting as a social choice rule?

Abstract

This article strengthens existing analysis concerning the effectiveness of majority rule. It demonstrates a one-to-one equivalence between the basic issue of social choice theory (the problem of selection of a well-functioning social choice rule [SCR]) and the problems that majority rule faces (it fails decisiveness in certain preference profiles). It is shown that whenever an SCR works well, majority rule works well, and in these circumstances, the SCR yields the same outcome as majority rule. So whenever majority rule works we can never do better by choosing an alternative SCR. When majority rule does not work well, then any other SCR will face a serious problem, too. The article defines the conditions underlying the concept of an SCR working well that enables these results to be established. © Oxford University Press 2014.