The impact and evolution of Medicare Part D.

cost problems in health care and the amount of money invested in mitigating these problems, the public, providers, and policymakers need to have confidence that money used to improve care is being well spent. It’s true that improvement science requires mixed methods and is difficult, but all good science is difficult. Failing to attend closely to issues of design, methods, and metrics leaves us with little confidence in an intervention. For the PPP, which required thousands of hours of clinicians’ time and large sums of money, that lack of confidence is particularly unfortunate. More important, the failure to generate valid, reliable information hampers our ability to improve future interventions, because we are no closer to understanding how to improve care than we were before the PPP. And that is the biggest cost of all.