Rees and Sabia 321
receiving a high school diploma by Wave III, and equal to zero if he or she failed to complete high school; and the third is equal to one if the respondent was attending
college at the time of the Wave III survey or had completed at least one year of college prior to being surveyed.
The independent variable of interest is Migraine. One parent, usually the mother, filled out a 40-minute questionnaire when the Wave I in-home survey was admin-
istered. They were presented with a list of “health problems,” and asked if their child, the respondent, was currently suffering from any of the problems on the list.
Migraine is equal to one if the parent indicated that the respondent had migraine
headaches, and is equal to zero if the parent indicated that they did not. In Table 1 we present unweighted means and standard deviations of the outcome
variables and Migraine by gender and for a combined sample of males and females.
3
According to the information in Table 1, a little over 10 percent of male Add Health respondents and 14 percent of female Add Health respondents suffered from mi-
graine headache. These figures are considerably higher than those reported by Bigal et al. 2007, who examined 12- through 19-year-olds, perhaps because Bigal et al.
2007 had enough information to apply the IHS criteria for what constitutes a migraine. If parents had trouble distinguishing between severe tension headaches or
secondary headaches and migraines, then the estimates below may understate the true effect of migraine headache on educational attainment.
4
Table 1 also shows the percentage of Add Health respondents with migraine head- ache by educational attainment. The patterns are pronounced and in keeping with
the results of Bigal et al. 2001 and Waldie et al. 2002: respondents whose high school GPA was below 3.5 were more likely to be migraineurs as compared to their
counterparts with GPAs above 3.5; high school dropouts were more likely to be migraineurs as compared to their counterparts who graduated high school; and re-
spondents who were not attending college at Wave III were more likely to be mig- raineurs as compared to their counterparts who were attending college.
IV. OLS Estimation Results
The negative relationship between suffering from migraines as an adolescent and educational attainment documented in Table 1 could be due to a
number of observable factors. For instance, it could be attributable to personal char- acteristics or socioeconomic status. In this section we use standard regression anal-
ysis to investigate these hypotheses.
Specifically, we estimate the following equation using OLS:
E ⳱ Ⳮ ⬘X Ⳮ Migraine Ⳮε ,
1
i 1
i 2
i i
where E
i
is a measure of respondent i’s educational attainment constructed from
answers to the Wave III Add Health survey; X
i
is a vector of controls; and Migraine
i
3. Weighting produces results similar to those reported in Table 1. 4. Distinguishing between migraine and tension headaches often can be difficult. Many migraine headaches
are accompanied by tension headache symptoms and vice versa Kaniecki 2002. Migraineurs often ex- perience frequent tension headache Lyngberg et al. 2005.
322 The Journal of Human Resources
Table 1 Means of Selected Variables by Gender
Combined Sample Males
Females High school GPA
2.55 2.40
2.69 0.828
0.834 0.796
[7,726] [3,734]
[3,992] High school graduation
0.827 0.800
0.852 0.379
0.400 0.355
[9,591] [4,658]
[4,931] College attendance
0.596 0.550
0.640 0.491
0.498 0.480
[9,593] [4,658]
[4,935] Migraine headache
0.122 0.102
0.142 0.328
0.302 0.349
[9,592] [4,657]
[4,935] GPA ⱖ 3.5
0.095 0.080
0.104 0.294
0.271 0.306
[1,055] [377]
[682] GPA ⬍ 3.5
0.122 0.097
0.148 0.328
0.298 0.355
[6,667] [3,357]
[3,310] High school graduation
0.116 0.096
0.133 0.320
0.295 0.339
[7,929] [3,726]
[4,203] Dropout
0.155 0.124
0.195 0.362
0.330 0.397
[1,662] [934]
[728] College
0.104 0.084
0.121 0.305
0.277 0.326
[5,718] [2,562]
[3,156] No college
0.149 0.124
0.179 0.356
0.330 0.383
[3,875] [2,096]
[1,779]
Note: Based on unweighted data drawn from Waves I and III of the National Longitudinal Study of Adolescent Health. Standard deviations are in parentheses and sample sizes are in brackets.
Rees and Sabia 323
is the indicator variable defined above. Our focus is on the estimate of 
2
. If 
2
is less than zero this could be interpreted as evidence that, as hypothesized, migraine
headache imposes a cost on suffers in terms of reduced human capital accumulation.
We include a large number of individual- and family-level variables in X
i
. Most are measured at Wave I, including the educational attainment of the parent who
answered the parental questionnaire, household income, parents’ marital status, the respondent’s Peabody Picture Vocabulary Test PPVT score a measure of cognitive
ability, race, ethnicity, height, body mass index BMI, and whether the respondent had an older sibling. A set of age dummies were constructed from information
available in the Wave III in-home survey.
OLS results for the full sample and by gender are presented in the first column of Table 2. Even controlling for family background and individual characteristics,
there is a strong negative relationship between migraine headache as an adolescent and educational attainment. Among male respondents, migraine headache is asso-
ciated with a 0.105 decrease in high school GPA and a 0.060 decrease in the prob- ability of attending college. Among females, migraine headache is associated with
a 0.079 decrease in high school GPA, a 0.051 decrease in the probability of gradu- ating high school, and a 0.076 decrease in the probability of attending college.
In terms of magnitude, the impact of migraine headache on educational attainment appears to be substantial. For instance, the average high school GPA of male Add
Health respondents in our sample was 2.40. Interpreting the OLS estimates as causal for the moment, they suggest that, among males, migraine headache leads to a 4.4
percent reduction 0.1052.40 in high school GPA. Or, to take another example, migraine headache is associated with an almost 12 percent decrease in the probability
that female respondents were attending college at the time of the Wave III interview.
V. Propensity Score Matching
