Information Aggregation in Spatial Committee Games

This paper introduces information aggregation into the standard spatial committee game. We assume that committee members must agree on a decision rule to aggregate their private information on a policy-relevant state of the world. We derive sucient conditions for the ex ante incentive compatible core to be nonempty, and provide some characterization results for incentive compatible core decision rules, called "durable decision rules". In particular, core points of the underlying complete-information game are shown to be constant, durable decision rules of the game with incomplete information if they satisfy some robustness property. Moreover, we show that durable decision rules exist whenever information is Pareto-improving relative to the core of the underlying complete-information game, provided that voters' private signals are weakly informative.