Obtaining follow-up interviews for treatment evaluation.

Studies of the outcomes of substance abuse treatment are often handicapped because of subjects lost to follow-up. While follow-up data may be obtained from several sources, the follow-up interview often serves as the principal source of data. Difficulties are regularly encountered in locating and interviewing subjects not in treatment. From review of the literature on follow-up methodology and our own experience, we identified 10 procedures for effective follow-up. Application of these procedures is illustrated in a follow-up study of illicit opioid users treated in a methadone maintenance program. Follow-up interviews were obtained with 98% of the subjects. We recommend use of the 10 procedures by follow-up researchers, and we also recommend review of several previous publications on follow-up methodology.