The effectiveness and ineffectiveness of complex behavioral interventions: Impact of treatment fidelity

There is often wide variability in the reported effects of complex behavioral interventions. Effectiveness can vary across studies, sites, and providers. A factor that has been insufficiently considered is the fidelity of the behavioral treatment that was provided. Low quality practice could be likened to partial doses of a vaccine or antibiotic: the right idea but insufficient strength. Using motivational interviewing (MI) as an example, the authors describe three quality conditions that should be present for a study to be regarded as a trial of a complex behavioral intervention: (1) The treatment should clearly contain the components that are theoretically or empirically related to its efficacy; (2) providers should be trained to an adequate and specified criterion of proficiency before treating trial patients; and (3) the fidelity of treatment should be documented by reliable coding of practice throughout the study and reported in a manner that permits comparison with skill levels in other trials. The authors also discuss bona fide intervention failures despite strong clinical trial methodology, offering recommendations for future outcome research. (C) 2014 Elsevier Inc. All rights reserved.