The treatment interventions distinguished under the OPI are long-term residential, short-term residential, intensive outpatient, regular outpatient, or urine monitoring only. The administering of the OPI involves a face-to-face interview that can be completed in approximately 30 minutes. It can be administered by any trained professional with basic interviewing skills. The assessment is essentially self-scoring, and a numerical score corresponds with a specific referral recommendation. The OPI and its associated service recommendations are based on "stakes in conformity," since research findings indicate that individuals with high stakes in conformity (as measured by educational attainment, employment history, living arrangements, and arrest history) are less likely to commit crimes than persons with low stakes in conformity. The background data and stake-in- conformity indices included in the OPI are sociodemographic and offense characteristics, drug severity index, family/support sub-index, education stake sub-index, school stake sub-index, work stake sub-index, home stake sub-index, criminal justice history sub-index, psychological stake sub- index, treatment stake sub-index, and HIV risk behaviors sub-index. Each of the indices and its scoring are discussed. A complete copy of the instrument is provided in a manner suitable for easy reproduction.