This paper by Hans Fehr (University of Wuerzburg) surveys recent advances in the field of computable general and partial equilibrium models. These advances take into account various aspects of uncertainty. He introduces the basic structure of an overlappinggenerations model with idiosyncratic labor income and mortality risk. Within this framework Fehr discusses the quantitative results of studies dealing with reform of the social security system. Next to that, models are brought up that focus on aggregate factor-productivity risk and/or demographic uncertainty.