Ex-addict versus nonaddict counselors' knowledge of clients' drug use.

The accuracy of drug counselors' knowledge of their clients' drug use was assessed to determine whether counselor reports might constitute adequate research and evaluation data. Ex-addict paraprofessionals, non-ex-addict paraprofessionals, and degreed professional counselors (N = 82) reported on the drug use by 302 methadone maintenance and drug-free outpatient clients, as did the clients themselves. Counselor nonresponse rates to individual drug category items were acceptably low (less than or equal to 5%) for all but marijuana/hashish and over-the-counter drugs. Counselors' estimates of drug use rates at a group level were relatively accurate. However, reliability coefficients reflecting accuracy on a case-by-case basis were lower than desirable for use in prediction schemes for individual clients. Ex-addicts were overall somewhat more accurate than the other counselor groups.