Working Paper: CEPR ID: DP6695
Authors: Laurent Bouton; Micael Castanheira
Abstract: This paper compares the properties of three electoral systems when voters have imperfect information. Imperfect information blurs voter decisions and may divorce the electoral outcome from the true preferences of the electorate. The challenge for electoral design is therefore to translate the (sometimes contradictory) elements of information dispersed in the electorate into the most efficient aggregate outcome. We propose a novel model of multi-candidate elections in Poisson games, and show that Approval Voting produces a unique equilibrium that is fully efficient: the candidate who wins the election is the one preferred by a majority of the electorate under full information. By contrast, traditional systems such as Plurality and Runoff elections cannot cope satisfactorily with information imperfections.
Keywords: Approval Voting; Information Aggregation; Multicandidate Elections; Poisson Games
JEL Codes: C72; D72; D81; D82
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Approval Voting (D72) | Unique Equilibrium (D59) |
| Unique Equilibrium (D59) | Candidate Preferred by Majority Wins (D79) |
| Approval Voting (D72) | Mitigates Risk of Disliked Candidate Winning (D79) |
| Imperfect Information (D83) | Approval Voting Outperforms Plurality and Runoff Elections (D72) |
| Approval Voting (D72) | Diminished Incumbency Advantage (D72) |
| Approval Voting (D72) | More Competitive Political Environment (D72) |