State governments contract with health maintenance organizations (HMOs) to coordinate medical care for nearly 20 million Medicaid recipients. Identifying the causal effect of HMO enrollment on government spending and health care quality is difficult if, as is often the case, recipients have the...

Public financing of private health insurance may generate external effects beyond the subsidized population, by influencing the size and bargaining power of health insurers. We test for this external effect in the context of Medicare Part D. We analyze how Part D-related insurer size increases...

I study the channels through which health insurance influences medical innovation. Following Medicare and Medicaid's passage, I find that U.S.-based medical-equipment patenting rose by 40 to 50 percent relative to both other U.S. patenting and foreign medical-equipment patenting. Within the...

We demonstrate Medicare's influence on private insurers' payments for physicians' services. Using a large administrative change in payments for surgical versus medical care, we find that private prices follow Medicare's lead. A $1 change in Medicare's fees moved private prices by $1.16. A second...