Medicare's Part D offers heavily subsidized new drug coverage to 22.5 million seniors to date, of whom 16.5 million are in stand-alone drug plans (Department of Health and Human Services, 2006). The government delegated the delivery of the benefit to private insurance companies arguing that...

Under Medicare Part D, senior citizens choose prescription drug insurance offred by numerous private insurers. We examine non-poor enrollees' actions in 2006 and 2007 using panel data. Our sample reduced overspending by $298 on average, with gains by 81% of them. The greatest improvements were...