Évaluation et comparaison des règles de vote derrière le voile de l’ignorance: Une brève revue de la littérature et une Analyse des règles de Scores à deux paramètres: Evaluating and Comparing Voting Rules behind the Veil of Ignorance: a Brief and Selective Survey and an Analysis of Two-Parameter Scoring Rules

Peter Postl

Research output: Contribution to journalArticlepeer-review

Abstract

We propose a general framework for the study and evaluation of voting rules behind the ‘veil of ignorance’. A selective review of the voting literature shows how many important contributions can be couched as special cases of this general framework. As many studies of voting rules for three or more candidates ignore the issue of strategic voting, and many fully-fledged mechanism
design approaches to the design of optimal voting rules focus on the case of elections with two candidates, we then present and discuss special case of the general framework in which the cardinal preferences of voters over three alternatives are private information. In this setting, we study voting rules that are two-parameter scoring rules, as introduced by Myerson (2002). For these voting rules, we show that all symmetric Bayes Nash equilibria are sincere, and have a very specific form. These equilibria are unique for a wide range of model parameters, and we can therefore compare the equilibrium performance of different rules. Computational results regarding the effectiveness of different scoring rules (where effectiveness is captured by a modification of the effectiveness measure proposed in Weber, 1978) suggest that those which most effectively represent voters’ preferences allow for the expression of preference intensity, in contrast to more commonly used rules such as the plurality rule, and the Borda Count. Whilst approval voting allows for the expression of preference intensity, it does not maximize effectiveness as it fails to unambiguously convey voters’ ordinal preference rankings.
Original languageFrench
Pages (from-to)249-290
Number of pages42
JournalL’Actualité économique
Volume93
Issue number1-2
Early online date2017
Publication statusPublished - 1 Mar 2017

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