Equilibrium and effectiveness of two-parameter scoring rules

Adam Giles, Peter Postl

Research output: Contribution to journalArticle

4 Citations (Scopus)
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Abstract

We study a cardinal model of voting with three alternatives where voters' von Neumann Morgenstern utilities are private information. We consider voting protocols given by 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. While 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 languageEnglish
Pages (from-to)31-52
Number of pages21
JournalMathematical Social Sciences
Volume68
Early online date24 Dec 2013
DOIs
Publication statusPublished - 1 Mar 2014

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Politics
Scoring
voting
Two Parameters
Voting
ranking
Private Information
Bayes
Nash Equilibrium
Scoring rules
Computational Results
Ranking
Count
Maximise
performance
Voters
Alternatives
Model
Range of data

Cite this

Equilibrium and effectiveness of two-parameter scoring rules. / Giles, Adam; Postl, Peter.

In: Mathematical Social Sciences, Vol. 68, 01.03.2014, p. 31-52.

Research output: Contribution to journalArticle

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