Jason M. Fletcher

Detecting implausible social network effects in acne, height, and headaches: longitudinal analysis.

Objective To investigate whether “network effects” can be detected for health outcomes that are unlikely to be subject to network phenomena. Design Statistical analysis common in network studies, such as logistic regression analysis, controlled for own and friend’s lagged health status. Analyses controlled for environmental confounders. Setting Subsamples of the National Longitudinal Study of Adolescent Health (Add Health). Participants 4300 to 5400 male and female adolescents who nominated a friend in the dataset and who were both longitudinally surveyed. Measurements Health outcomes, including headache severity, acne severity, and height self reported by respondents in 1994-5, 1995-6, and 2000-1. Results Significant network effects were observed in the acquisition of acne, headaches, and height. A friend’s acne problems increased an individual’s odds of acne problems (odds ratio 1.62, 95% confidence interval 0.91 to 2.89). The likelihood that an individual had headaches also increased with the presence of a friend with headaches (1.47, 0.93 to 2.33); and an individual’s height increased by 20% of his or her friend’s height (0.18, 0.15 to 0.26). Each of these results was estimated by using standard methods found in several publications. After adjustment for environmental confounders, however, the results become uniformly smaller and insignificant. Conclusions Researchers should be cautious in attributing correlations in health outcomes of close friends to social network effects, especially when environmental confounders are not adequately controlled for in the analysis.

Child Mental Health and Human Capital Accumulation: The Case of Adhd Revisited

In volume 25, issue 6 of this journal, Janet Currie and Mark Stabile (JCMS,) made a significant contribution to our understanding of the influence of ADHD symptoms on a variety of school outcomes including participation in special education, grade repetition and test scores. Their contributions include using a broad sample of children and estimating sibling fixed effects models to control for unobserved family effects. In this comment we look at a sample of older children and confirm and extend many of the JCMS findings in terms of a broader set of measures of human capital and additional specifications.

Adolescent Depression and Educational Attainment: Results Using Sibling Fixed Effects

This paper contributes to the literature on the relationship between adolescent depression and educational attainment in several ways. First, while cross-sectional data are normally used, this paper uses longitudinal data in order to defend against the potential of reverse causality. Second, this is the first paper in the literature to control for sibling-fixed effects in examining the relationship between adolescent depressive symptoms and human capital accumulation. Importantly, this eliminates omitted factors such as family and neighborhood characteristics common to siblings that affect both depressive symptoms and educational attainments (e.g. neighborhood crime, and family resources). Third, this paper examines the effects of both an indicator and scale of depressive symptoms and finds important associations with these depressive symptoms and human capital accumulation. Though the results cannot be given a causal interpretation, the findings show a negative relationship between depressive symptoms and years of schooling. The relationship appears to be driven primarily through increasing the chances of dropping out but may have small impacts on the likelihood of college attendance (conditional on high school graduation). In particular, preferred estimates suggest that a standard deviation increase in depressive symptoms is associated with a 25-30% increase in the likelihood of dropping out.

Genetic and educational assortative mating among US adults

Significance It is well established that individuals are more similar to their spouses than other individuals on important traits, such as education level. The genetic similarity, or lack thereof, between spouses is less well understood. We estimate the genome-wide genetic similarity of spouses and compare the magnitude of this value to a comparable measure of educational similarity. We find that spouses are more genetically similar than two individuals chosen at random but this similarity is at most one-third the magnitude of educational similarity. Furthermore, social sorting processes in the marriage market are largely independent of genetic dynamics of sexual selection. Understanding the social and biological mechanisms that lead to homogamy (similar individuals marrying one another) has been a long-standing issue across many fields of scientific inquiry. Using a nationally representative sample of non-Hispanic white US adults from the Health and Retirement Study and information from 1.7 million single-nucleotide polymorphisms, we compare genetic similarity among married couples to noncoupled pairs in the population. We provide evidence for genetic assortative mating in this population but the strength of this association is substantially smaller than the strength of educational assortative mating in the same sample. Furthermore, genetic similarity explains at most 10% of the assortative mating by education levels. Results are replicated using comparable data from the Framingham Heart Study.

Taxing Soft Drinks And Restricting Access To Vending Machines To Curb Child Obesity

One of the largest drivers of the current obesity epidemic is thought to be excessive consumption of sugar-sweetened beverages. Some have proposed vending machine restrictions and taxing soft drinks to curb childrens consumption of soft drinks; to a large extent, these policies have not been evaluated empirically. We examine these policies using two nationally representative data sets and find no evidence that, as currently practiced, either is effective at reducing childrens weight. We conclude by outlining changes that may increase their effectiveness, such as implementing comprehensive restrictions on access to soft drinks in schools and imposing higher tax rates than are currently in place in many jurisdictions.

Long-Term Consequences of Childhood ADHD on Criminal Activities

BACKGROUND Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most prevalent mental health problems facing children. Little is known of the long-term consequences of ADHD on young adult outcomes. AIMS OF THE STUDY We examine the associations between childhood ADHD symptoms and criminal activities as a young adult. METHODS We use a nationally representative study of US adolescents and logistic regression analysis to examine our research question. We also control for common family factors using sibling random and fixed effects and test the robustness of our results in several ways. RESULTS The empirical estimates show that children who experience ADHD symptoms face a substantially increased likelihood of engaging in many types of criminal activities. An included calculation of the social costs associated with criminal activities by individuals with childhood ADHD finds the costs to be substantial. DISCUSSION Our study provides the first evidence using a nationally representative dataset of the long term consequences on criminal activities of childhood ADHD. Our results are quite robust to a number of specification checks. Limitations of our study include that our measures of ADHD are retrospective, we have no information on treatment for ADHD, and it remains possible that our results are confounded by unmeasured variables. IMPLICATIONS Our results suggest that children showing ADHD symptoms should be viewed as a group at high risk of poor outcomes as young adults. As such, a good case can be made for targeting intervention programs on this group of children and conducting evaluations to learn if such interventions are effective in reducing the probability that these children commit a crime. Development of such intervention programs and evaluating them for efficiency could be dollars well spent in terms of crime and drug abuse averted.

Childhood mistreatment and adolescent and young adult depression

In this paper, I use a nationally representative sample of adolescents from the United States to examine the association between childhood mistreatment (sexual abuse and physical abuse) and depression during adolescence and young adulthood. Researchers have implicated childhood mistreatment as one of the most important predictors of depression. An alternative mechanism linking childhood mistreatment with adolescent and young adult depression is community and family disadvantage (or other factors) that affect both outcomes. Using data from the restricted version of the U.S. National Longitudinal Study of Adolescent Health (Add Health), this paper outlines several findings of the relationship between mistreatment and depression as well as the gender differences in depression. First, I find very limited evidence that controlling for common environmental factors at the school or neighborhood level explain the relationship between mistreatment and depression. Also, I show that controlling for common family factors decreases the predictive power of childhood mistreatment on depression. Results in this paper generally support previous research that shows the link between childhood mistreatment and depression is most important for females, even within families. Finally, results suggest that the effects of child mistreatment on depression may increase as individuals age.

The Effects of Intimate Partner Violence on Health in Young Adulthood in the United States

This paper uses data on a national sample of adolescents from the United States followed through the transition into young adulthood to examine the association between intimate partner violence (IPV) and health outcomes, including depressive symptoms, self reported health status, and health care utilization. Researchers have shown an important IPV-health link in a number of settings but have often been limited by using cross-sectional data, convenience samples, and the inability to control for important risk factors and confounders. The findings from this study suggests that these limitations likely inflate the estimated link between IPV and health by as much as 60% but also show that IPV has important health impacts on a number of outcomes. The results also show no differential impact of IPV by gender or previous exposure to child abuse. The health effects of IPV are also typically larger for current exposure than previous exposure, but each exposure type is shown to reduce health.

Identifying Patients at Increased Risk for Unplanned Readmission

Background:Reducing readmissions is a national priority, but many hospitals lack practical tools to identify patients at increased risk of unplanned readmission. Objective:To estimate the association between a composite measure of patient condition at discharge, the Rothman Index (RI), and unplanned readmission within 30 days of discharge. Subjects:Adult medical and surgical patients in a major teaching hospital in 2011. Measures:The RI is a composite measure updated regularly from the electronic medical record based on changes in vital signs, nursing assessments, Braden score, cardiac rhythms, and laboratory test results. We developed 4 categories of RI and tested its association with readmission within 30 days, using logistic regression, adjusted for patient age, sex, insurance status, service assignment (medical or surgical), and primary discharge diagnosis. Results:Sixteen percent of the sample patients (N=2730) had an unplanned readmission within 30 days of discharge. The risk of readmission for a patient in the highest risk category (RI<70) was >1 in 5 while the risk of readmission for patients in the lowest risk category was about 1 in 10. In multivariable analysis, patients with an RI<70 (the highest risk category) or 70–79 (medium risk category) had 2.65 (95% confidence interval, 1.72–4.07) and 2.40 (95% confidence interval, 1.57–3.67) times higher odds of unplanned readmission, respectively, compared with patients in the lowest risk category. Conclusion:Clinicians can use the RI to help target hospital programs and supports to patients at highest risk of readmission.

Race and Ethnic Differences in College Achievement: Does High School Attended Matter?

Using ten years of enrollment data at four Texas public universities, the authors examine whether, to what extent, and in what ways high school attended contributes to racial and ethnic differences in college achievement. As with previous studies, the authors show that controlling for class rank and test scores shrinks, but does not eliminate, sizable racial differences in college achievement. Fixed-effects models that take into account differences across high schools that minority and nonminority youth attend largely eliminate, and often reverse, black-white and Hispanic-white gaps in several college outcomes. The results, which are quite robust across universities of varying selectivity, illustrate how high school quality foments race and ethnic inequality in college performance.