A Note on: Jury Size and the Free Rider Problem

Abstract

This note reassesses the basic result in Mukhopadhaya (2003) that, when jurors may acquire costly signals about a defendant’s guilt, with a larger jury size the probability of reaching a correct verdict may in fact fall, contrary to the Condorcet Jury Theorem. We show that if the jurors coordinate on any one of a number of (equally plausible) asymmetric equilibria other than the symmetric equilibrium considered by Mukhopadhaya, the probability of accuracy reaches a maximum for a particular jury size and remains unchanged with larger juries, thus mitigating Mukhopadhaya’s result somewhat. However, the case for limiting the jury size a recommendation by Mukhoapdhaya gains additional grounds if one shifts the focus from maximizing the probability of reaching a correct verdict to the maximization of the overall social surplus, measured by the expected benefits of jury decisions less the expected costs of acquiring signals.jury size, free rider problem, Condorcet Jury Theorem