The What Works Clearinghouse (WWC) aims to synthesize and disseminate the results of high-quality education research on areas of significant public interest. The WWC has come to serve as a concrete example of the growing willingness of the federal government to shape both the topic and methods chosen by researchers. However, the scope of research…

Beginners in many disciplines learn that correlation never proves causation, but sometimes, even in public health, correlation, mistaken for causation, becomes the basis for policy and great expenditures of public and private money. "True experiments" with random assignment to experimental and control groups hold a special place in the…