Background: It is well documented that the results of most behavioral and health promotion studies have not been translated into practice. Purpose: In this article, reasons for this gap, focusing on study design characteristics as a central contributing barrier, are discussed. Methods: Four reviews of recent controlled studies in work sites, health care, school, and community settings are briefly discussed and summarized. Their implications for future research and for closing the gap between research and practice are then discussed. Results: These reviews come to consistent conclusions regarding key internal and external validity, factors that have and have not been reported. It is very clear that moderating variables and generalization issues have not been included or reported in the majority of investigations, and that as a consequence little is known about the representatives or the robustness of results from current studies. Conclusions: To significantly improve the current state of affairs, substantial changes will be required on the part of researchers, funding agencies, and review and editorial boards. In conclusion, recommendations for each of these entities are provided.