Theoretical Economics, Volume 11, Number 3 (September 2016)

Theoretical Economics 11 (2016), 865–895

Condorcet meets Ellsberg

Andrew Ellis


The Condorcet Jury Theorem states that given subjective expected utility maximization and common values, the equilibrium probability that the correct candidate wins goes to one as the size of the electorate goes to infinity. This paper studies strategic voting when voters have pure common values but may be ambiguity averse -- exhibit Ellsberg-type behavior -- as modeled by maxmin expected utility preferences. It provides sufficient conditions so that the equilibrium probability of the correct candidate winning the election is bounded above by one half in at least one state. As a consequence, there is no equilibrium in which information aggregates.

Keywords: Ambiguity, voting, elections, information aggregation

JEL classification: D72, D81

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