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...

Studies examining the effectiveness of welfare-to-work programs present findings that are mixed and sometimes at odds, in part due to research design, data, and methodological limitations of the studies. We aim to substantially improve on past approaches to estimate program effectiveness by...