A story in the New York Times today on the effectiveness of colonoscopy highlights the importance of evaluating the effectiveness of action. One of the biggest areas of study in academic policy research is evaluation, and the federal government has an entire agency that focuses on evaluation in the Government Accountability Office.

But in policy as in medicine – as the colonoscopy case illustrates — it is amazing how often evaluation of the effectiveness of action is overlooked or simply not done. Evaluation matters because it indicates what is working and what works. In the case of colonoscopy, improved health outcomes are apparently achieved with only a minor change in medical practice.