J. DRUG EDUCATION, Vol. 33(1) 25-47, 2003 PREDICTORS OF SUBSTANCE ABUSE TREATMENT OUTCOMES IN TENNESSEE* SATISH KEDIA, PH.D. CHARLES WILLIAMS, PH.D. The University of Memphis, Tennessee ABSTRACT In planning and implementing programs to treat substance abuse, it is impor- tant to understand which factors influence post-treatment abstinence. This article identifies and analyzes several variables important in predicting the likelihood of abstinence among substance abuse clients. The data used in this study was collected from 1,350 clients treated for alcohol or drug abuse in residential, halfway house, or outpatient facilities in Tennessee. We analyzed 22 variables as possible treatment outcome predictors by using two statis- tical procedures: stepwise logistic regression analysis and Quick, Unbiased, Efficient, Statistical Tree (QUEST) analysis, a tree-structured classification algorithm analysis. We found one pre-treatment, five in-treatment, and three post-treatment variables to be significant predictors of treatment outcome: previous treatment history, perceived helpfulness of the treatment, simul- taneous treatment for mental health, number of days in treatment, completion of treatment, special skills training during treatment, obtaining healthcare services for major physical health problem after treatment, living with someone using alcohol or drugs post treatment, and arrest record since treatment. *The authors would like to thank the Bureau of Alcohol and Drug Abuse Services at the Tennessee Department of Health for funding this project and for providing data collected by treatment facilities in Tennessee. 25 Ó 2003, Baywood Publishing Co., Inc.