This paper explores the potential of an approach suggested by Manski of obtaining nonparametric bounds for treatment effects in evaluation studies without knowledge of the participation process. The practical concern is the effects of continuous vocational training in East Germany. The empirical...

The paper studies the returns from enterprise-related continuous vocational training on individual earnings, unemployment probabilities, and other labor market indicators in East Germany after unification. It attempts to solve the intrinsic identification problem of such evaluation problems...