Essays in Health Economics

Abstract

This dissertation consists of three chapters, each representing a self-contained research paper in health economics.

The first chapter studies the methods used to quantify the impact of the provision in the Affordable Care Act that lets young adults stay on their parents’ insurance. Several recent papers use broad age-time difference-in-differences strategies to argue that this causes significant health insurance and labor effects. Using SIPP and CPS data, I show that difference-in-differences models over “placebo” dates also produce statistically significant “effects” long before ACA implementation, even with conservative standard errors and matching adjustments. This suggests that the effects attributed to the ACA could instead reflect dynamics in the age-structure of the health insurance and labor markets. Reducing the age bandwidth yields more reliable estimates of the increases in parental and overall insurance coverage. The key problem in this literature is therefore potentially overstating the “effects” of the ACA in other dimensions. (JEL codes: I13, I18, J08)

In the second chapter (joint with Yao Lu), I examine the impact of women’s health clinic closures on women’s preventive care use in Texas and Wisconsin using a unique policy context, data on clinic street addresses, and confidential respondent ZIP codes from the Behavioral Risk Factor Surveillance System. From a within-ZIP-code analysis, we conclude that an increase of 100 miles to the nearest clinic results in a decrease in the annual utilization rate of a clinical breast exam by 11 percent, a mammogram by 18 percent, and a Pap test by 14 percent. These estimates are generally larger for women of lower educational attainment. (JEL codes: H75, I18, J13)

In the third chapter (joint with Nils Wernerfelt and Richard Zeckhauser), I examine the recent medical hypothesis speculates that maternal vitamin D levels during pregnancy affect the probability the fetus later develops asthma. In two large-scale studies, we test this hypothesis using a natural experiment afforded by historical variation in sunlight, a major source of vitamin D. We show that this measurement of sunlight correlates with actual exposure, and consistent with pre-existing results from the fetal development literature, we find substantial and highly significant evidence in both datasets that increased sunlight during the second trimester lowers the subsequent probability of asthma. Our results suggest policies designed to augment vitamin D levels in pregnant women, the large majority of whom are vitamin D insufficient, could be very cost-effective and yield a substantial surplus. (JEL codes: I12, I18, J13)