Information Aggregation and Preference Heterogeneity in Committees∗

This paper is concerned with the efficiency of information aggrega-tion in a committee whose members have heterogeneous preferences over a binary decision variable. In a first stage, agents may exchange private (decision-relevant) information which is assumed to be verifiable. Then they reach a decision via majority voting. We study different information environments and identify conditions under which full information aggre-gation is possible. In particular, if preferences are common knowledge and each committee member is endowed with information full informa-tion aggregation is possible despite preference heterogeneity