TREATMENT FIDELITY IN OUTCOME STUDIES

Fidelity of treatment in outcome research refers to confirmation that the manipulation of the independent variable occurred as planned. Verification of fidelity is needed to ensure that fair, powerful, and valid comparisons of replicable treatments can be made. The central purpose of this article is the evaluation of outcome studies from 1980 to 1988 to determine the extent to which investigators are attending adequately to the issue of treatment fidelity. The evaluation covered 359 treatment outcome studies from major journals in four domains: clinical psychology, behavior therapy, psychiatry, and marital and family therapy. The studies were evaluated with respect to: (a) the training of treatment implementors, (b) the procedures used to promote fidelity, (c) the aspects of treatment verified, (d) the methods for assessing fidelity, and (e) the utilization of fidelity assessment in the interpretation of results. Although there were significant increases over the decade in the percentage of studies that checked adherence to treatment and used supervision to promote fidelity, the majority (55%) of the studies essentially ignored the issue of treatment fidelity. Furthermore, only one out of eight studies in the most recent period (1986-1988) combined the use of treatment manuals, supervision of treatment agents, and checking of adherence to protocol. Finally, attention given to the aforementioned aspects of fidelity did not differ significantly across journal domains. The overall implication of the review of existing practices is that investigators, reviewers, and journal editors need to give even greater consideration to the issues associated with fidelity. Specific recommendations for improving the promotion and verification of treatment fidelity in outcome studies were offered. © 1991.