A Model of Repeated Collective Decisions

Abstract

The theory of repeated games offers a compelling rationale for cooperation in a variety of environments. Yet, its consequences for collective decision-making have been largely unexplored. In this paper, we propose a general model of repeated voting in committees and study equilibrium behavior under alternative majority rules. Our main characterization reveals a complex relationship between the majority threshold, the preference distribution, and the set of equilibrium payoffs. In contrast with the stage game, equilibria in the repeated game may involve a form of implicit logroll, individuals sometimes voting against their preference to achieve the efficient decision. In turn, this affects the optimal voting rule, which may significantly differ from the optimal rule under sincere voting. The model provides a rationale for the use of unanimity rule, while accounting for the prevalence of consensus in committees which use a lower majority threshold.