An index of problem severity at intake was defined using variables representing functional domains commonly related to treatment goals and outcomes. Eight indicators were scored to reflect "problems" in these domains. The patient problem severity index is the sum of the presence of these 8 problems (range, 0-8); the index was further classified into low (0-2), medium (3-5), and high (6-8) levels of severity. The indicators were multiple drug use (use of ≥3 drugs during the year before treatment), dependence on alcohol or any drug (by DSM-III-R criteria16), mental disorder (conduct disorder, attention-deficit/hyperactivity disorder, panic disorder, anxiety disorder, or major depressive disorder, using DSM-III-R criteria), criminal involvement, unstable living arrangement, family alcohol and other drug (AOD) problems, deviant reference group, and academic failure prior to DATOS-A treatment. Patients were considered criminally active if they were on probation or parole, awaiting trial or had a case pending at intake, or reported a period of weekly involvement in illegal activities during the past year. The unstable living arrangement scale ranged from 0 to 9 (with a greater value indicating greater instability) and was the summed presence of the following conditions: receiving supplemental security income (0 = no; 1 = yes), not having adequate food or shelter (0 = no; 1 = yes), living in an unstable residence (range, 1-3; 1 = house or condominium; 2 = mobile home, apartment, or other multiple family building; 3 = hotel, boarding house, homeless shelter), number of places lived (range, 1-3), and not living with parents (0 = no, 1 = yes). The scale for family AOD problems had a range of 0 to 5, with 5 being the most problematic, and is the summed presence of AOD problems among the adolescent's mother, father, mother's relatives, father's relatives, and sisters or brothers. Scores on the deviant reference group ranged between 0 and 12 (with a greater value indicating greater severity) by counting the number of family members and friends who used drugs, drank alcohol heavily, had been arrested, or were jailed. An academic failure scale (range, 0-9, with a greater value indicating greater failure) considered repeating grades (range, 0-2; 0 = no, 1 = once, 2 = more than once); being suspended (range 0-2; 0 = no, 1 = once, 2 = more than once) or expelled (range, 0-2; 0 = no, 1 = once, 2 = more than once); skipping school (0 = no, 1 = yes); and whether first expulsion, suspension (0 = younger than 15 years, 1 = 15 years or older), or truancy occurred prior to age 15 years (0 = younger than 15 years, 1 = 15 years or older). Most problem indicators were dichotomous variables, and a median split was used for those with continuous scales (ie, unstable living arrangement, family AOD problems, deviant reference group, and academic failure).