METHODOLOGICAL OVERVIEW AND RESEARCH DESIGN FOR THE DRUG-ABUSE TREATMENT OUTCOME STUDY (DATOS)

The Drug Abuse Treatment Outcome Study (DATOS) is the 3rd in a series of national multisite studies of community-based treatment sponsored b y the National Institute on Drug Abuse. The major goal of this prospec tive cohort study of adult clients entering treatment from 1991 to 199 3 is to evaluate treatment effectiveness. The study included 10,010 ad missions from 96 programs in 11 cities. Interviews were conducted at a dmission and during treatment, and 2,966 selected participants complet ed a 12-month follow-up interview. This article describes the methodol ogical aspects of the study and provides an overview of program and cl ient samples. Data collection procedures and instrumentation are descr ibed, and the analytical approach used to attain the research objectiv es is presented. Future plans for a longer term follow-up are also des cribed, along with the potential contributions of DATOS findings to tr eatment policy.