Evaluating the impact of health promotion programs: using the RE-AIM framework to form summary measures for decision making involving complex issues.

Current public health and medical evidence rely heavily on efficacy information to make decisions regarding intervention impact. This evidence base could be enhanced by research studies that evaluate and report multiple indicators of internal and external validity such as Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) as well as their combined impact. However, indices that summarize the combined impact of, and complex interactions among, intervention outcome dimensions are not currently available. We propose and discuss a series of composite metrics that combine two or more RE-AIM dimensions, and can be used to estimate overall intervention impact. Although speculative and, at this point, there have been limited empirical data on these metrics, they extend current methods and are offered to yield more integrated composite outcomes relevant to public health. Such approaches offer potential to help identify interventions most likely to meaningfully impact population health.