Communication, Renegotiation and Coordination with Private Values (Extended Version)

An equilibrium is communication-proof if it is unaffected by new opportunities to communicate and renegotiate. We characterize the set of equilibria of coordination games with pre-play communication in which players have private preferences over the feasible coordinated outcomes. Communication-proof equilibria provide a narrow selection from the large set of qualitatively diverse Bayesian Nash equilibria in such games. Under a communication-proof equilibrium, players never miscoordinate, play their jointly preferred outcome whenever there is one, and communicate only the ordinal part of their preferences. Moreover, such equilibria are robust to changes in players' beliefs, interim Pareto efficient, and evolutionarily stable.