The NASADAD used a working group approach to instrument development, an expert panel of clinicians and researchers in the fields of drug abuse and criminology, to devise specific content areas and measurement questions. Content areas included family support, education, school, employment, home/residential stability, criminal justice involvement, psychological functioning, and drug treatment history. In addition, a drug severity index was developed that yielded a numerical score based on drug use type and frequency. The OPI is not a clinical instrument designed to produce a comprehensive drug abuse treatment plan. Rather, it is a broad classification instrument to determine what type of drug abuse treatment intervention is appropriate. Administering the OPI involves a face-to-face interview that can be completed in about 30 minutes. Procedures to follow in using and scoring the OPI are described, and the complete OPI is attached.