Nonparametric bounds on treatment effects with imperfect instruments

This paper extends the identification results in Nevo and Rosen (2012) to nonparametric models. We derive nonparametric bounds on the average treatment effect when an imperfect instrument is available. As in Nevo and Rosen (2012), we assume that the correlation between the imperfect instrument and the unobserved latent variables has the same sign as the correlation between the endogenous variable and the latent variables. We show that the monotone treatment selection and monotone instrumental variable restrictions, introduced by Manski and Pepper (2000, 2009), jointly imply this assumption. Moreover, we show how the monotone treatment response assumption can help tighten the bounds. The identified set can be written in the form of intersection bounds, which is more conducive to inference. We illustrate our methodology using the National Longitudinal Survey of Young Men data to estimate returns to schooling.

Spearman’s Hypothesis in the Vietnam Experience Study and National Longitudinal Survey of Youth ‘79

There are few empirically derived theories explaining group differences in cognitive ability. Spearman's hypothesis is one such theory which holds that group differences are a function of a given test's relationship to general intelligence, g. Research into this hypothesis has generally been limited to the application of a single method lacking sensitivity, specificity, and the ability to assess test bias: Jensen’s method of correlated vectors. In order to overcome the resulting empirical gap, we applied three different psychometrically sound methods to examine the hypothesis among American blacks and whites in the Vietnam Experience Study (VES) and the National Longitudinal Survey of Youth 1979 (NLSY ‘79). We first used multi-group confirmatory factor analysis to assess bias and evaluate the hypothesis directly; we found that strict factorial invariance was tenable in both samples and either the strong or the weak form of the hypothesis was supported, with 87 and 78% of the group differences attributable to g in the VES and NLSY ’79 respectively. Using item response theory metrics to avoid pass rate confounding, a strong relationship between g loadings and group differences (r = 0.80 and 0.79) was observed. Finally, assessing differential item functioning with item level data revealed that a handful of items functioned differently, but their removal did not affect gap sizes much beyond what would be expected from shortening tests, and assessing the effect this had on scores using an anchoring method, the differential functioning was found to be negligible in size. In aggregate, results supported Spearman's hypothesis but not test bias as an explanation for the cognitive differences between the groups we studied.

Maternal Economic Well-Being and Mental Health among Young Adult Children: Race/Ethnicity

This study aimed to examine the relationship between maternal economic well-being and children’s mental health outcomes in adulthood and to consider the moderating effect of race/ethnicity. This study used data from the National Longitudinal Survey of Youth 1979 and the National Longitudinal Survey of Youth 79 for Children and Young Adults. The two datasets were merged, and 4224 pairs were selected for the final sample. Ordinary linear regression and logistic regression analyses were used. Poverty and lower net worth among mothers were positively associated with their children’s depression in young adulthood. Race/ethnicity moderated the relationship between maternal poverty and children’s depression. Therefore, women’s economic resources may be an important factor in the development of mental health issues among their children in young adulthood. Developing anti-poverty policies that target women may assist in reducing depressive symptoms in their children once they reach young adulthood, specifically for non-Hispanic White children.

Initial Industry and Long-Term Earnings Growth

We test whether employment growth in a male worker's initial industry influences earnings growth using the 1979 National Longitudinal Survey of Youth. We follow workers for 20 years after reporting their first industry, finding that lower employment growth in their initial industry implies substantially lower earnings growth. Notably, after controlling for observable skills, controls for family background and region have no impact on estimates. Effects appear larger for initial occupations that involve more routine or manual tasks as well as for occupations that involve less abstract tasks, but these differences are not statistically significant.

Depressive Symptom Trajectories and Early Adult Education and Employment: Comparing Longitudinal Cohorts in Canada and the United States

Adolescent depressive symptoms are risk factors for lower education and unemployment in early adulthood. This study examines how the course of symptoms from ages 16–25 influences early adult education and employment in Canada and the USA. Using data from the National Longitudinal Survey of Children and Youth (n = 2348) and the National Longitudinal Survey of Youth 79 Child/Young Adult (n = 3961), four trajectories (low-stable; increasing; decreasing; and increasing then decreasing, i.e., mid-peak) were linked to five outcomes (working with a post-secondary degree; a high school degree; no degree; in school; and NEET, i.e., not in employment, education, or training). In both countries, increasing, decreasing, and mid-peak trajectories were associated with higher odds of working with low educational credentials, and/or NEET relative to low-stable trajectories. In Canada, however, all trajectories had a higher predicted probability of either being in school or working with a post-secondary degree than the other outcomes; in the USA, all trajectory groups were most likely to be working with a high school degree. Higher depressive symptom levels at various points between adolescent and adulthood are associated with working with low education and NEET in Canada and the USA, but Canadians are more likely to have better education and employment outcomes.