Here is an abstract from Sebastian Bauhoff:
This paper evaluates whether health plans in Germany's Social Health Insurance select on an easily observable predictor of risk: geography. To identify plan behavior separately from concurrent demand-side adverse selection, I implement a double-blind audit study in which plans are contacted by fictitious applicants from different locations. I find that plans are less likely to respond and follow-up with applicants from higher-cost regions, such as West Germany. The results suggest that supply-side selection may emerge even in heavily regulated insurance markets.
Here are relevant comments from Aaron Carroll:
Such insurance [on the exchanges] is going to have to come with restrictions. There might be network restrictions (such as seeing only certain providers). There might be gateways people don’t like. And there might be other rules in place that people don’t anticipate.
My conversations lead me to believe that many people are expecting that the plans offered in the exchanges will be Medicare-like in many ways. I feel like many people think they will have choice of doctor, choice of hospital, and the ability to dictate care. I’m not seeing how insurance companies will be able to offer such products at prices people can afford. As I talk to more and more people in the insurance industry, my thoughts seem confirmed.