The reliability of Form 90: an instrument for assessing alcohol treatment outcome

Project MATCH is a randomized clinical trial consisting of five outpatient and five aftercare units at nine sites. Of importance in this multisite trial examining the efficacy of client-treatment matching was the cross- and within-site reliability of the structured interview used to assess alcohol treatment outcomes, the Form 90. Evaluation of the reliability of Form 90 is the subject of this article.

The reliability of Form 90 was evaluated in two test-retest studies. The cross-site reliability study consisted of 70 paired test-retest interviews conducted by different interviewers. Clients for this study were recruited from inpatient, outpatient and college settings. The within-site reliability study had a total of 108 paired test-retest interviews, with 54 of the retests conducted by different interviewers and 54 by the same interviewer. Clients for this study were most often presenting for alcohol treatment at the nine sites and were selected to be representative of the larger Project MATCH sample.

Good-to-excellent reliability was found for all key summary measures of alcohol consumption and psychosocial functioning, and most frequently used illicit drugs had moderate reliability. No decay in consistency of self-reported drinking was found at more distal points from dates of test-retest interviews. Application of 68% confidence intervals for primary alcohol consumption measures suggests that trained researchers and clinicians can obtain consistent information regarding client drinking.

Form 90 appears to be a reliable instrument for alcohol treatment assessment research when interviewers have received careful training and supervision in its use.