A Condorcet Jury Theorem for Large <i>Poisson</i> Elections with Multiple Alternatives

Herein, we prove a Condorcet jury theorem (CJT) for large elections with multiple alternatives. Voters have common interests that depend on an unknown state of nature. Each voter receives an imprecise private signal about the state of nature and then submits one vote (simple plurality rule). We also...

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Main Author: Johanna M. M. Goertz
Format: Article
Language:English
Published: MDPI AG 2019-12-01
Series:Games
Subjects:
Online Access:https://www.mdpi.com/2073-4336/11/1/2
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author Johanna M. M. Goertz
author_facet Johanna M. M. Goertz
author_sort Johanna M. M. Goertz
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description Herein, we prove a Condorcet jury theorem (CJT) for large elections with multiple alternatives. Voters have common interests that depend on an unknown state of nature. Each voter receives an imprecise private signal about the state of nature and then submits one vote (simple plurality rule). We also assume that this is a Poisson voting game with population uncertainty. The question is whether the simple plurality rule aggregates information efficiently so that the correct alternative is elected with probability tending to one when the number of voters tends to infinity. The previous literature shows that the CJT holds for large elections with two alternatives, but there is also an example of a large election with three alternatives that has an inefficient equilibrium. We show that there always exists an efficient equilibrium, independent of the number of alternatives. Under certain circumstances (informative types), it is unique in elections with two alternatives. The existence of inefficient equilibria in elections with more than two alternatives is generic.
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spelling doaj.art-910d2e059dec41d7abd283ee1b41eac72022-12-22T00:03:31ZengMDPI AGGames2073-43362019-12-01111210.3390/g11010002g11010002A Condorcet Jury Theorem for Large <i>Poisson</i> Elections with Multiple AlternativesJohanna M. M. Goertz0Department of Economics and Finance, Gordon S. Lang School of Business and Economics, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, CanadaHerein, we prove a Condorcet jury theorem (CJT) for large elections with multiple alternatives. Voters have common interests that depend on an unknown state of nature. Each voter receives an imprecise private signal about the state of nature and then submits one vote (simple plurality rule). We also assume that this is a Poisson voting game with population uncertainty. The question is whether the simple plurality rule aggregates information efficiently so that the correct alternative is elected with probability tending to one when the number of voters tends to infinity. The previous literature shows that the CJT holds for large elections with two alternatives, but there is also an example of a large election with three alternatives that has an inefficient equilibrium. We show that there always exists an efficient equilibrium, independent of the number of alternatives. Under certain circumstances (informative types), it is unique in elections with two alternatives. The existence of inefficient equilibria in elections with more than two alternatives is generic.https://www.mdpi.com/2073-4336/11/1/2efficient information aggregationsimple plurality rulepoisson gamescondorcet jury theorem
spellingShingle Johanna M. M. Goertz
A Condorcet Jury Theorem for Large <i>Poisson</i> Elections with Multiple Alternatives
Games
efficient information aggregation
simple plurality rule
poisson games
condorcet jury theorem
title A Condorcet Jury Theorem for Large <i>Poisson</i> Elections with Multiple Alternatives
title_full A Condorcet Jury Theorem for Large <i>Poisson</i> Elections with Multiple Alternatives
title_fullStr A Condorcet Jury Theorem for Large <i>Poisson</i> Elections with Multiple Alternatives
title_full_unstemmed A Condorcet Jury Theorem for Large <i>Poisson</i> Elections with Multiple Alternatives
title_short A Condorcet Jury Theorem for Large <i>Poisson</i> Elections with Multiple Alternatives
title_sort condorcet jury theorem for large i poisson i elections with multiple alternatives
topic efficient information aggregation
simple plurality rule
poisson games
condorcet jury theorem
url https://www.mdpi.com/2073-4336/11/1/2
work_keys_str_mv AT johannammgoertz acondorcetjurytheoremforlargeipoissonielectionswithmultiplealternatives
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