Much of the extensive empirical literature on insurance markets has focused on whether adverse selection can be detected. Once detected, however, there has been little attempt to quantify its importance. We start by showing theoretically that the efficiency cost of adverse selection cannot be...

We present a simple graphical framework to illustrate the potential welfare gains from a “top-up” health insurance policy requiring patients to pay the incremental price for more expensive treatment options. We apply this framework to breast cancer treatments, where lumpectomy with radiation...