Abstract

Consider a health policy issue like child car seats in the U.S., mosquito netting in the third world, preschool education for poor children, or the immunization of immigrants. Imagine that for this issue there were many good studies over several decades, including some recent studies. Imagine that after controlling for many factors, these studies usually found that variations in spending or usage were significantly, substantially, and positively related to variations in health. Furthermore, imagine this result was confirmed by a thirty year old randomized experiment.