The U.S. Preventive Services Task Force (USPSTF) makes recommendations on which preventive services to routinely incorporate into primary care for specific populations. Behavioral counseling interventions are preventive services designed to help persons engage in healthy behaviors and limit unhealthy ones. The USPSTF's evaluation of behavioral counseling interventions asks 2 primary questions: Do interventions in the clinical setting influence persons to change their behavior, and does changing health behavior improve health outcomes with minimal harms?This article discusses challenges encountered by the USPSTF in aggregating the behavioral counseling intervention literature to develop guidelines. The challenges relate broadly to study populations, intervention protocols, assessment of outcomes, and linking behavior changes to health outcomes. Recommendations to address these challenges include use of the PRECIS (Pragmatic-Explanatory Continuum Indicator Summary) tool as a guide for the development of feasible, replicable, and generalizable behavioral counseling interventions; improved reporting of study methods and results; consensus measures for key behavioral outcomes; and use of existing data sets to link behavior change and clinical outcomes.