Envisioning an improved research strategy for detecting moderators/mediators in intervention studies: A commentary on McClure et al.

The goal of moderator/mediator research in treatment evaluation is to provide guidance to clinicians to choose the best treatment for each patient with a disorder (moderators), and to advise on its optimal protocol or implementation (mediators): personalized/precision medicine. McClure et al. report a systematic review of studies addressing moderators/mediators of the treatment effect of digital interventions for eating disorders, finding no robust moderators or mediators. They attribute this failure to methodological problems, an assessment with which I concur. The focus of this discussion is to clarify which methodological approaches are not likely to be successful, and to envision a research strategy encompassing both hypothesis-generating (exploratory) and hypothesis-testing approaches likely to produce better results not only for eating disorders, but also for all medical treatments.