"The rise of HMOs was enabled by an earlier federal government attempt to rein in health care costs, the Health Maintenance Organization Act of 1973. The idea behind HMOs was that these insurers would control costs by offering a wide array of preventive care to their subscribers. That sounds like a plausible idea until one realizes that people, on average, change insurers every four years or so. An insurer that invested in preventive care was unlikely to reap the cost-saving benefits."

That's an interesting response to the HMO phenomenon, which I remember was touted as a solution to ballooning health care costs. The cost containment didn't happen, which is an important lesson for today's predictions about efforts to contain health care costs.