PROPORTIONAL VOTING RULE

Abstract: this paper shows that under the unrestricted domain of strict preferences; a neutral, anonymous and Pareto-optimal voting rule is self-equivalent if and only if it is proportional. A voting rule is proportional if and only if it assigns to every alternative the proportion of voters for whom that alternative is top-ranked; it is neutral if and only if it is independent of alternatives’ labels; it is anonymous if and only if it is independent of voters’ names; it is Pareto-optimal if and only if it assigns null weight to all Pareto-dominated alternatives; and it is self-equivalent if and only if it always induces a lottery over sets of decisive voting rules that coincides with itself.

Author: Hector Hermida-Rivera.

Keywords: voting, proportionality, neutrality, anonymity, Pareto-optimality, self-equivalence.

JEL Codes: D71, D82.