This informal paper explores models of competitve insurance market equilibrium when individuals of initially similar apparent risk experience divergence in risk levels over time. The information structrue is modeled in three alternative ways: all insurers and insureds know risk at any point in...

"Employers must determine which sorts of healthcare insurance plans to offer employees and also set employee premiums for each plan provided. Depending on how they structure the premiums that employees pay across different healthcare insurance plans, plan sponsors alter the incentives to choose...

This paper investigates a possible predictor of adverse selection problems in unsubsidized stand-alone' prescription drug insurance: the persistence of an individual's high spending over multiple years. Using MEDSTAT claims data and data from the Medicare Survey of Current Beneficiaries, we find...