An examination of theory and behavior change in randomized clinical trials.

This paper underscores the important role played by theory-based mediating variables in randomized clinical trials. Indeed, it is essential that we know what mediating variables are relevant for particular outcomes in randomized clinical trials and that we design interventions to optimize change in the mediators of interest. Yet, knowledge of the pivotal mediating variables in behavior change does not imply that we know how to intervene effectively. This gap may be due to the fact that existing research typically has been designed to garner support for theory, as opposed to testing support for behavior change strategies that are based on theory. In addition, we argue that there are important mediating variables in behavior change that have not been given systematic attention in theory development. For example, behavior change must be viewed as a collaborative process, and participants' perceptions concerning the feasibility of change is important to motivational processes in randomized clinical trials. Control Clin Trials 2000;21:164S-170S