On Condorcet's Jury Theorem with Abstention

Fuente: arXiv
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Main Authors: Meir, Reshef, Ghalme, Ganesh
Format: Preprint
Published: 2025
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author Meir, Reshef
Ghalme, Ganesh
author_facet Meir, Reshef
Ghalme, Ganesh
contents The well-known Condorcet Jury Theorem states that, under majority rule, the better of two alternatives is chosen with probability approaching one as the population grows. We study an asymmetric setting where voters face varying participation costs and share a possibly heuristic belief about their pivotality (ability to influence the outcome). In a costly voting setup where voters abstain if their participation cost is greater than their pivotality estimate, we identify a single property of the heuristic belief -- weakly vanishing pivotality -- that gives rise to multiple stable equilibria in which elections are nearly tied. In contrast, strongly vanishing pivotality (as in the standard Calculus of Voting model) yields a unique, trivial equilibrium where only zero-cost voters participate as the population grows. We then characterize when nontrivial equilibria satisfy a version of the Jury Theorem: below a sharp threshold, the majority-preferred candidate wins with probability approaching one; above it, both candidates either win with equal probability.
format Preprint
id arxiv_https___arxiv_org_abs_2510_18062
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On Condorcet's Jury Theorem with Abstention
Meir, Reshef
Ghalme, Ganesh
Computer Science and Game Theory
Multiagent Systems
The well-known Condorcet Jury Theorem states that, under majority rule, the better of two alternatives is chosen with probability approaching one as the population grows. We study an asymmetric setting where voters face varying participation costs and share a possibly heuristic belief about their pivotality (ability to influence the outcome). In a costly voting setup where voters abstain if their participation cost is greater than their pivotality estimate, we identify a single property of the heuristic belief -- weakly vanishing pivotality -- that gives rise to multiple stable equilibria in which elections are nearly tied. In contrast, strongly vanishing pivotality (as in the standard Calculus of Voting model) yields a unique, trivial equilibrium where only zero-cost voters participate as the population grows. We then characterize when nontrivial equilibria satisfy a version of the Jury Theorem: below a sharp threshold, the majority-preferred candidate wins with probability approaching one; above it, both candidates either win with equal probability.
title On Condorcet's Jury Theorem with Abstention
topic Computer Science and Game Theory
Multiagent Systems
url https://arxiv.org/abs/2510.18062