Commitee Decisions: Optimality And Equilibrium

The authors consider a committee facing a binary decision under uncertainty. Each member holds some private information. Members may have different preferences and initial beliefs, but they all agree which decision should be taken in each of the two states of the world. They characterize the optimal anonymous and deterministic voting rule and provide a homogeneity assumption on preferences and beliefs under which sincere voting is a Nash equilibrium for this rule. They also provide a necessary and sufficient condition for sincere voting to be equilibrium under any deterministic majoritarian voting rule. They show that a class of slightly randomized majoritarian voting rules makes sincere voting a strict and unique equilibrium.