This article argues that evaluation of drug courts will benefit not only from an organizing typology (Goldkamp, 1999a, 2000) that focuses research on the critical structural elements of the drug court model, but also from an understanding of how drug courts are viewed as delivering their impact.
In developing a causal model of drug court impact, the analysis separates assessment of impact into two investigations: whether drug courts "work" and how they work. Data from the ongoing National Institute of Justice-supported evaluation of the Portland and Las Vegas drug courts were analyzed to determine whether or not they had an impact and, if so, what kind of impact. The analysis then considered the internal elements of the drug court (the "black box" of drug court treatment) through the development of successive theoretical models. The illustrative analyses guided by these models considered the relative contributions of instrumental drug court treatment functions and defendant risk attributes, which contributed significantly to drug court outcomes. The exploratory findings differed by site, but showed some support for the importance of treatment, sanctions, and appearances before the drug court judge, as well as their interaction, in lowering the prospects for subsequent rearrest and increasing likelihood of graduation. 13 figures, 7 tables, 21 notes, and 16 references