I estimate the long term effect of military service on quantiles of earnings and education using the Vietnam draft lottery eligibility status as an instrument. I compare the local quantile treatment effect estimator studied by Abadie, Angrist, and Imbens (2002) to the instrumental variables quantile regression technique developed by Chernozhukov and Hansen (2008). Ordinary quantile regression shows a large negative association between service in Vietnam and earnings of white men, with the effect increasing in magnitude for the upper quantiles. Quantile treatment effects estimates show the opposite pattern, although much smaller in magnitude, with a small negative effect at the lower end of the distribution, and a small positive effect at the upper end. This suggests the ordinary quantile result is due to heterogeneous selection effects. The two methods of quantile treatment effects estimation give similar results.
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Did Vietnam Veterans Get Sicker in the 1990s? The Complicated Effects of Military Service on Self-Reported Health
August 2009
Working Paper Number:
CES-09-19
The veterans disability compensation (VDC) program, which provides a monthly stipend to disabled veterans, is the third largest American disability insurance program. Since the late 1990s, VDC growth has been driven primarily by an increase in claims from Vietnam veterans, raising concerns about costs as well as health. We use the draft lottery to study the long-term effects of Vietnam-era military service on health and work in the 2000 Census. These estimates show no significant overall effects on employment or work-related disability status, with a small effect on non-work-related disability for whites. On the other hand, estimates for white men with low earnings potential show a large negative impact on employment and a marked increase in non-work-related disability rates. The differential impact of Vietnam-era service on low-skill men cannot be explained by more combat or war-theatre exposure for the least educated, leaving the relative attractiveness of VDC for less skilled men and the work disincentives embedded in the VDC system as a likely explanation.
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The Impact of College Education on Old-Age Mortality: A Study of Marginal Treatment Effects
January 2017
Working Paper Number:
CES-17-30
Using a newly constructed dataset that links 2000 U.S. Census long-form records to Social Security Administration data files, I evaluate the effect of college education on mortality. In an OLS regression, women and men who have at least some college education have 20% lower mortality rates than those with a high school degree or less. I proceed with an empirical design intended to illuminate the extent to which this relationship is causal, estimating marginal treatment effects (MTEs) using the proximity of the nearest college to individuals' birthplace as an instrument. Results indicate positive selection into college education (in terms of longevity) for both women and men. Selection drives almost all of the mortality gap for women. For men, longevity gains from college attendance are concentrated among individuals with unobserved variables that make them unlikely attend college. This suggests that men who would benefit most from receiving college education in terms of mortality reductions are those who are not attending.
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Long-Term Effects of Vietnam-Era Conscription: Schooling, Experience and Earnings
August 2007
Working Paper Number:
CES-07-23
Instrumental variables (IV) estimates using the draft lottery show that white Vietnam-era draftees suffered substantial post-service earnings losses in the 1970s and 1980s. Angrist (1990) explains these losses as due primarily to lost labor market experience. Non-public use data from the 2000 Census allow the first longerterm follow-up for a large sample from the draft-lottery cohorts. We use these data to estimate the effects of military service on earnings, schooling, and a number of other variables. Consistent with the loss-of -experience model, IV estimates of the effects of Vietnam-era service on earnings are close to zero in 2000, when the draft-lottery cohorts were middle-aged and experience profiles relatively flat. On the other hand, draft-lottery estimates show a marked increase in schooling for Vietnam-era veterans. A variety of evidence suggests this increase reflects the impact of the Vietnam-era GI Bill more than draft-avoidance behavior. The economic return to the increased schooling generated by Vietnam-era service, estimated in a wage equation that constrains the impact of Vietnam-era military service to run solely through the experience and schooling channels, appears to be less than the OLS return. Finally, we look at measures of disability. The IV estimates point to an increase in non-workrelated disability rates and non-SSA disability income, but the fact that there is no corresponding effect on employment, hours worked, or work-related disability rates suggests health was affected little by Vietnam-era service. Allowing for excess disability among veterans raises the estimated returns to GI-Bill schooling slightly.
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The Effects of Smoking in Young Adulthood on Smoking and Health Later in Life: Evidence Based on the Vietnam Era Draft Lottery
September 2008
Working Paper Number:
CES-08-35
An important, unresolved question for health policymakers and consumers is whether cigarette smoking in young adulthood has significant lasting effects into later adulthood. The Vietnam era draft lottery offers an opportunity to address this question, because it randomly assigned young men to be more likely to experience conditions favoring cigarette consumption, including highly subsidized prices. Using this natural experiment, we find that military service increased the probability of smoking by 35 percentage points as of 1978-80, when men in the relevant cohorts were aged 25-30, but later in adulthood this effect was substantially attenuated and did not lead to large negative health effects.
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Run Effects of Military Service: Evidence from the 911 Attacks
November 2021
Working Paper Number:
CES-21-36
We investigate the effect of military service on labor market, health and family formation outcomes, leveraging differential changes in enlistment rates brought about by the September 11th attacks (911). Using restricted microdata, we identify hundreds of 'high service" counties in which certain birth-county cohorts exhibit large enlistment responses to 911. We find that individuals born into high service counties between 1977 and 1983 (aged 18-24 at the time of the attack), enlisted at nearly twice the rate of earlier birth cohorts (older than 24 at the time of the attack). These high service birth-county cohorts experienced a 10% increase in wages, decreased unemployment and impacts on other labor market measures as well as key household formation measures including marriage and fertility. We also find increases in the hospitalization and mortality rates. Labor market benefits outweigh mortality costs at standard discount rates.
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Universal Preschool Lottery Admissions and Its Effects on Long-Run Earnings and Outcomes
March 2023
Working Paper Number:
CES-23-09
We use an admissions lottery to estimate the effect of a universal (non-means tested) preschool program on students' long-run earnings, income, marital status, fertility and geographic mobility. We observe long-run outcomes by linking both admitted and non-admitted individuals to confidential administrative data including tax records. Funding for this preschool program comes from an Indigenous organization, which grants Indigenous students admissions preference and free tuition. We find treated children have between 5 to 6 percent higher earnings as young adults. The results are strongest for individuals from the lower half of the household income distribution in childhood. Likely mechanisms include high-quality teachers and curriculum.
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Military Service and Immigrants' Integration: Evidence From the Vietnam Draft Lotteries
June 2026
Working Paper Number:
CES-26-35
Seminal theories in political science argue that military service is a critical driver of minority integration. However, a major obstacle bedeviling the study of military service is self-selection: individuals who are better integrated may be more likely to join the military in the first place. We address the selection problem by examining the effects of military conscription during the Vietnam War using an instrumental variables approach. Conscription during 1970--72 was decided on the basis of national draft lotteries that assigned draft numbers based on an individual's date of birth. Using the draft lottery instrument, we find no evidence of a causal effect of military service on a range of integration outcomes from the 2000 decennial census. At least for the Vietnam era, the link between service and long-term integration is largely driven by self-selection, which points to important scope conditions for the integrationist view.
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Head Start and Mothers' Work: Free Child Care or Something More?
March 2018
Working Paper Number:
CES-18-13
Head Start is the largest public pre-school program in the US, but it provides many additional services to families. This paper uses a discontinuity in grant writing assistance in the first year of the Head Start program to identify impacts on the work and welfare usage of mothers. Using restricted Decennial Census and administrative AFDC data I find that Head Start decreases employment rates and hours worked per week for single mothers. I also find a suggestive increase in welfare receipt for single mothers which is confirmed by an increase in the share of administrative welfare case-files that are single mother households. For all mothers combined there are no significant changes in work or welfare use. I also estimate long-run impacts, 10 years after a woman's child was eligible for Head Start. I find large and persistent declines in work for both non-white mothers and single mothers, accompanied by an increase in public assistance income and return to school. I argue that this is consistent with the 1960's era Head Start program's focus on encouraging quality parenting, parent participation and helping families access all benefits for which they were eligible.
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The Work Disincentive Effects of the Disability Insurance Program in the 1990s
February 2006
Working Paper Number:
CES-06-05
In this paper we evaluate the work disincentive effects of the Disability Insurance program during the 1990s. To accomplish this we construct a new large data set with detailed information on DI application and award decisions and use two different econometric evaluation methods. First, we apply a comparison group approach proposed by John Bound to estimate an upper bound for the work disincentive effect of the current DI program. Second, we adopt a Regression-Discontinuity approach that exploits a particular feature of the DI eligibility determination process to provide a credible point estimate of the impact of the DI program on labor supply for an important subset of DI applicants. Our estimates indicate that during the 1990s the labor force participation rate of DI beneficiaries would have been at most 20 percentage points higher had none received benefits. In addition, we find even smaller labor supply responses for the subset of 'marginal' applicants whose disability determination is based on vocational factors.
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EARNINGS ADJUSTMENT FRICTIONS: EVIDENCE FROM SOCIAL SECURITY EARNINGS TEST
September 2013
Working Paper Number:
CES-13-50
We study frictions in adjusting earnings to changes in the Social Security Annual Earnings Test (AET) using a panel of Social Security Administration microdata on one percent of the U.S. population from 1961 to 2006. Individuals continue to "bunch" at the convex kink the AET creates even when they are no longer subject to the AET, consistent with the existence of earnings adjustment frictions in the U.S. We develop a novel framework for estimating an earnings elasticity and an adjustment cost using information on the amount of bunching at kinks before and after policy changes in earnings incentives around the kinks. We apply this method in settings in which individuals face changes in the AET bene.t reduction rate, and we estimate in a baseline case that the earnings elasticity with respect to the implicit net-of-tax share is 0.23, and the .xed cost of adjustment is $152.08.
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