David Slusky

Significant Placebo Results in Difference-in-Differences Analysis: The Case of the ACA’s Parental Mandate

The Affordable Care Act (ACA) lets young adults stay on their parents’ insurance. Several papers use age–time difference-in-differences strategies to argue this causes health insurance and labor effects. I show that difference-in-differences over “placebo” dates also produces statistically significant “effects” before ACA implementation, even with conservative adjustments. This suggests 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 ACA’s “effects” in other dimensions.

Second Trimester Sunlight and Asthma: Evidence from Two Independent Studies

One in 12 Americans suffers from asthma, and its annual costs are estimated to exceed

Measuring the ACA’s Parental Mandate Using Difference-in-Differences

50 billion. Yet the root causes of the disease remain unknown. A recent hypothesis posits that maternal vitamin D levels during pregnancy affect the probability the fetus later develops asthma. Employing two large-scale studies, we test this hypothesis using a natural experiment afforded by historical variation in sunlight, a major source of vitamin D. Specifically, holding the birth location and month fixed, we see how exogenous within-location variation in sunlight across birth years affects the probability of asthma onset. We show that this measurement of sunlight correlates with actual exposure, and consistent with preexisting results from the fetal development literature, we find substantial and highly significant evidence in both data sets 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.

The Impact of Women’s Health Clinic Closures on Fertility

The Affordable Care Act 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 extent of increases in insurance coverage.The Patient Protection and Affordable Care Act of 2010 mandates that young adults be able to stay on parental health insurance until age 26. This paper creates a new algorithm to identify individuals with parental health insurance. Using an age/time difference-in-difference analysis, it finds that this federal mandate increased insurance coverage by 3-4 percentage points. Parental insurance rose by 7-9 percentage points, but own coverage fell by 4-5 percentage points. The mandate also caused substitution from full-time to part-time work and from four-year private to two-year public colleges. Treated young adults were also 2-3 percentage points more likely to have a personal doctor and 1-2 percentage points less likely to have forgone care due to cost, and their households spent an average of

Health, Employment, and Disability: Implications from the Undocumented Population

45-

With and without the tracks: how railroad access impacts gas price elasticity

60 per three months less on health insurance.

Birth Spacing and Educational Outcomes

In recent years, the government of Texas has enacted multiple restrictions and funding limitations on womens health organizations affiliated with the provision of abortion services. These policies have caused numerous clinic closures throughout the state, drastically reducing access to reproductive health care. We study the impact of these clinic closures on fertility rates by combining quarterly snapshots of health center addresses from a network of womens health centers with restricted geotagged data of all Texas birth certificates for 2008–13. We calculate the driving distance to the nearest clinic for each zip code and quarter, and find that an increase of 100 miles to the nearest clinic results in a 1.2 percent increase in the fertility rate. This increase is driven by a 2.4 percent increase in the fertility rate for unmarried women, while there is no statistically significant change for married women.

The Impact of Women's Health Clinic Closures on Preventive Care

Disability benefit recipients in the United States have nearly doubled in the past two decades, growing substantially faster than the population. It is difficult to estimate how much of this increase is explained by changes in population health, as we often lack a valid counterfactual. We propose using undocumented immigrants as the counterfactual, as they cannot currently claim benefits. Using NHIS microdata, we estimate models of disability as a function of medical conditions for both the legal and undocumented populations. The relationship between health and disability is far stronger for those with legal status than it is for those who are undocumented. We find that almost all of the difference in disability trends between the two populations can be explained by different responses to underlying health impairments. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

Sunlight and Protection Against Influenza

ABSTRACT Since 2011, gas prices have fallen 43%, raising the question of how different communities adjust their vehicle miles travelled. Data from the National Household Travel Survey’s EPA fuel economy database and the Energy Information Administration database are used to measure consumers’ elasticity to changes in gas prices. We find no significant difference between the price elasticity of individuals in cities with rail access and those without. Furthermore, we are able to rule out an elasticity in those with rail that is greater than 0.61, suggesting that rail access does not make consumer demand elastic.

Did Medicaid Expansion Reduce Medical Divorce

Virtually all parents want their children to succeed academically. How to achieve this goal, though, is far from clear. Specifically, the temporal spacing between adjacent births has been shown to affect educational outcomes. While many of these studies have produced substantial and statistically significant results, these results have been relatively narrow in their application due to data limitations. Using Colorado birth certificates matched to schooling outcomes, we investigate the relationship between birth spacing and educational attainment. We instrument birth spacing with a previous pregnancy that did not result in a live birth. We find no overall effect of spacing on either the first or second children’s grade 3-10 test scores. Stratifying by the sexes of the children, we find that when the first child is a boy and the second a girl, an extra year of spacing increases the first child’s math, reading, and writing test scores by 0.07-0.08 SD, while there is no impact on the second child. This is the first study to do such an analysis using matched large scale birth and elementary to high school administrative data, and to leverage a very large data set to stratify our results by the sexes of the children. .