Competition among health insurers, revisited.

This paper updates our 1977 study of health insurance competition. We find that insurers are now far more willing to compete by controlling costs. Large consumer copayments and insurer utilization controls, once deemed politically infeasible, have become commonplace. HMOs and especially PPOs are booming. Blue Shield and Blue Cross market share and market power are declining. We discuss why the insurance market has changed and conclude with thoughts on the future.