This paper investigates the effects of market-wide changes in health insurance by examining the single largest change in health insurance coverage in American history: the introduction of Medicare in 1965. I estimate that the impact of Medicare on hospital spending is over six times larger than what the evidence from individual-level changes in health insurance would have predicted. This disproportionately larger effect may arise if market-wide changes in demand alter the incentives of hospitals to incur the fixed costs of entering the market or of adopting new practice styles. I present some evidence of these types of effects. A back of the envelope calculation based on the estimated impact of Medicare suggests that the overall spread of health insurance between 1950 and 1990 may be able to explain about half of the increase in real per capita health spending over this time period.

Public policies designed to increase utilization of existing technologies may also affect incentives to develop new technologies. This paper investigates this phenomenon by examining policies designed to increase usage of preexisting vaccines. I find that these policies were associated with a 2.5-fold increase in clinical trials for new vaccines. For several diseases, the induced innovation is socially wasteful, though small in magnitude. In one case, however, the "dynamic" social welfare benefits from induced innovation exceed the policies' "static" benefits from increasing vaccination with existing technology. These findings underscore the importance of including technological progress in economic analysis of public policy.