An evaluation of an alcohol and drug treatment program for homeless substance abusers

This article evaluates a residential alcohol/drug treatment program for the homeless. The process evaluation documents numerous deviations from the program as designed and other implementation problems. Foremost among these: The project was designed as a randomized experiment, but randomization was sabotaged by the treatment staff. Nonrandom research attrition constituted another potential source of bias, The authors employ econometric modeling techniques to correct for these selection biases. Results indicate that, although treatment effects are in the expected direction, they an rarely significant However consistent with the drug treatment literature, evidence suggests that retention in treatment is a critical variable predicting program effects. Clients who remain in treatment for more than a few months exhibit more positive outcomes than those staying for shorter periods.