Robustness of Subgame Perfect Implementation

In this paper we consider the robustness of subgame perfect implementation in situations when the preferences of players are almost perfectly known. More precisely, we consider a class of information perturbations where in each state of the world players know their own preferences with certainty and receive almost perfectly informative signals about the preferences of other players. We show that implementations using two-stage sequential move mechanisms are always robust under this class of restricted perturbations, while those using more stages are often not