The first chapter examines the impacts of health care provider exits on patient outcomes and subsequent reallocation. Using administrative data on the universe of nursing home patients, I estimate the mortality effects of 1,109 nursing home closures on incumbent residents with a matched difference-in-differences approach. I find that displaced residents face a short-run 15.7% relative increase in their mortality risk. Yet this increase is offset by long-run survival improvements, so the cumulative effect inclusive of the initial spike is a net decline in mortality risk. These gains are driven by patients reallocating to higher quality providers. I also find significant heterogeneity by local market conditions: the survival gains accrue only to patients in competitive nursing home markets, whereas residents in concentrated markets experience no survival improvements. I then develop and estimate a dynamic model of the nursing home industry with endogenous exit. Combining the model estimates with the mortality results, I examine the effects of counterfactual reimbursement policy experiments on nursing home closures and resident life expectancy. A universal 10% increase in the Medicaid rate decreases the frequency of closures, but causes some low-quality providers to remain open in competitive areas. In contrast, targeted subsidies for facilities in areas with limited alternatives improves overall life expectancy by averting the costliest nursing home closures. In the second chapter (co-authored with Szymon Sacher), we estimate a mortality-based Bayesian model of nursing home quality accounting for selection. We then conduct three exercises. First, we examine the correlates of quality, and find that public report cards have near-zero correlation. Second, we show that higher quality nursing homes fared better during the pandemic: a one standard deviation increase in quality corresponds to 2.5% fewer Covid-19 cases. Finally, we show that a 10% increase in the Medicaid reimbursement rate raises quality, leading to a 1.85 percentage point increase in 90-day survival. Such a reform would be cost-effective under conservative estimates of the quality-adjusted statistical value of life. The third chapter (co-authored with Michael Barnett and Adam Sacarny) examines why efforts to raise the productivity of the U.S. health care system have proceeded slowly. One potential explanation is the fragmentation of payment across insurers. Each insurer's efforts to improve care could influence how doctors practice medicine for other insurers, leading to unvalued externalities. We study these externalities by examining the unintended private insurance spillovers of a public insurer's intervention. In 2015, Medicare randomized warning letters to doctors to curtail overuse of antipsychotics. Even though the letters did not mention private insurance, they reduced prescribing to privately insured patients by 12%. The reduction to Medicare patients was 17%, and we cannot reject one-for-one spillovers. If private insurers conducted a similar intervention with their own limited information, they would stem half as much prescribing as a social planner able and willing to better target the intervention. Our findings establish that insurers can affect health care well outside their direct purview, raising the question of how to match their private objectives with their scope of influence.