Seldom are health policy decisions guided solely—or even primarily—by evidence from clinical trials. Indeed, there may be an inherent mismatch between the broad scope and rapid speed of most policy decisions and the deliberate specificity and methodical pace of traditional trial research. Policymakers often adopt or fund interventions for broad populations based on incomplete information, and under time pressure, budgetary constraints, and competing political demands. Clinical trialists, in contrast, may focus on generating internally valid answers to highly specific questions under carefully controlled conditions, a process that can take years of planning, data collection, and analysis. Not surprisingly, policymakers may perceive that the evidence generated by trials is too limited and arrives too late to guide many of the real-world decisions they make, while trialists may lament that sweeping policy actions are taken without robust experimental evidence demonstrating their effects.