High Quality Content by WIKIPEDIA articles! Bayesian efficiency addresses an appropriate economic definition of Pareto efficiency where there is incomplete information. Under Pareto efficiency, an allocation of a resource is Pareto efficient if there is no other allocation of that resource that makes no one worse off while making some agents strictly better off. A limitation with the concept of Pareto efficiency is that it assumes that knowledge about other market participants is available to all participants in that every player knows the payoffs and strategies available to other players so as to have incomplete information. Often, the players have types that are hidden from the other player.