This article presents the authors' rejoinder to the comments of Howard Bloom, Derek Neal, and Mike Seltzer on their article. Their commentary focused foremost on the advantages and disadvantages of using Options A, B, or C in using instrumental variables in multisite trials. Of interest are the quantities one can estimate and test in each case,…

This paper addresses the question: How does implementation influence the effectiveness of mandatory welfare-to-work programs? Data from three large-scale, multi-site random assignment experiments were pooled; quantitative measures of program implementation were constructed; and multilevel statistical modeling was used to examine the relationship…