DescriptionThis retrospective study attempts to identify variables predictive of treatment dropout, using the information collected in the New Jersey Substance Abuse Monitoring System, a data collection program based on the Addiction Severity Index, and used by the large majority of substance abuse treatment programs in the State. Client characteristics, client/clinician interaction, program characteristics/environment and practical barriers to treatment were examined as potential predictors of dropout. The dependent variable was completed treatment/quit or dropped out. The sample consisted of all clients (704), 184 women and 520 men whose primary drug of abuse was alcohol, who were treated in large drug free outpatient program between January 1, 2004 and May 31, 2007, at a medical center in Union County, New Jersey. The mean age of the subjects was 39.8 years. A series of bivariate analyses were performed using Chi-Square and t tests to select a group of potential predictor variables. These were then used as independent variables in logistic regressions in an attempt to find the variables with the best predictive validity for treatment dropout. Length of stay was found to be a good predictor of dropout, with clients with shorter lengths of stay being more likely to leave treatment before completion. Level of treatment intensity, assessed by the program the client was referred to (Standard Outpatient, Intensive Outpatient, or Partial Hospital) was also found to predict dropout, with clients treated in the Standard Outpatient Program more than three times as likely to complete treatment as those treated in the other two programs. The predictive validity for dropout for some variables were different for men than for women –for men, but not for women, living with their children, and being mandated into treatment reduced the likelihood of dropout. Women who used alcohol and one other drug were 3.5 times as likely to drop out as women using alcohol only, but the number of drugs used was not predictive of dropout for men. The study tested whether subjects with more severe bio-psycho-social problems, as measured by the sum of the ASI composite scores, were more at risk of dropout, however this proved unfounded.