This study seeks to demonstrate a method for treatment effect estimation in a multisite observational study where the treatment is highly selective and the assignment mechanism varies across sites. The method is demonstrated by addressing three primary research questions about the effect of 8th grade algebra: (1) For students who take algebra in…

This article engages students in a simulation of the Coat Check problem, in which four women check their coats only to have them returned at random. Students examine the experimental and theoretical probability of at least one woman getting her own coat back.