How to Use Decision Theory to Choose Among Mechanisms

We extend a recently introduced approach to the positive problem of game the-ory, Predictive Game Theory (PGT Wolpert (2008)). In PGT, modeling a game results in a probability distribution over possible behavior profiles. This contrasts with the conventional approach where modeling a game results in an equilibrium set of possible behavior profiles. We analyze three PGT models. Two of these are based on the well-known quantal response and epsilon equilibrium concepts, while the third is entirely new to the economics literature. We use a Cournot game to demonstrate how to use our extension of PGT, concentrating on model combina-tion, modeler uncertainty, and mechanism design. In particular, we emphasize how PGT allows a modeler to perform prediction and mechanism design in a manner that is fully consistent with decision theory. We do this even in situations where conventional approaches yield multiple equilibria, an ability that is necessary for a fully decision theoretic mechanism design. Where possible, PGT results are com-pared against equilibrium set analogs. We would like to thank George Judge, Julian Jamison, Alan Isaac and audience members at th