Helena Skyt Nielsen

Employment and Wage Assimilation of Male First Generation Immigrants in Denmark

Labour market assimilation of Danish first generation male immigrants is analysed based on two panel data sets covering the population of immigrants and 10% of the Danish population during 1984-1995. Wages and employment probabilities are estimated jointly in a random effects model which corrects for unobserved cohort and individual effects and panel selectivity due to missing wage information. The results show that immigrants assimilate partially to Danes, but the assimilation process differs between refugees and non-refugees.

Is There a Causal Effect of High School Math on Labor Market Outcomes

In this paper, we exploit a high school pilot scheme to identify the causal effect of advanced high school math on labor market outcomes. The pilot scheme reduced the costs of choosing advanced math because it allowed for a more flexible combination of math with other courses. We find clear evidence of a causal relationship between math and earnings for students who are induced to choose math after being exposed to the pilot scheme. The effect partly stems from the fact that these students end up with a higher education.

Discrimination and detailed decomposition in a logit model

Abstract The paper suggests how to use the logit model to decompose the gender difference in the probability of an occurrence. The technique is illustrated by an analysis of formal sector employment in urban Zambia.

Five-Fold Increase in National Prevalence Rates of Attention-Deficit/Hyperactivity Disorder Medications for Children and Adolescents with Autism Spectrum Disorder, Attention-Deficit/Hyperactivity Disorder, and other Psychiatric Disorders: A Danish Register-Based Study

OBJECTIVE The purpose of this study was to estimate the prevalence and time trends in prescriptions of methylphenidate, dexamphetamine, and atomoxetine in children and adolescents, within three diagnostic groups: 1) autism spectrum disorder (ASD), 2) attention-deficit/hyperactivity disorder (ADHD), and 3) other psychiatric disorders. METHODS Data from six different national registers were used and merged to identify a cohort of all children and adolescents born in Denmark between 1990 and 2001 (n=852,711). Sociodemographic covariates on cohort members and their parents and lifetime prescriptions of methylphenidate, dexamphetamine, and atomoxetine were extracted from the registers. Prescriptions were also stratified by duration (<6 months. vs.≥ 6 months). RESULTS Sixteen percent of 9698 children and adolescents with ASD (n=1577), 61% of 11,553 children and adolescents with ADHD (n=7021) and 3% of 48,468 children and adolescents with other psychiatric disorders (n=1537) were treated with one or more ADHD medications. There was a significant increase in prescription rates of these medications for all three groups. From 2003 to 2010, youth 6-13 years of age with ASD, ADHD, and other psychiatric disorders had 4.7-fold (4.4-4.9), 6.3-fold (6.0-6.4), and 5.5-fold (5.0-5.9) increases, respectively, in prescription rates of ADHD medications. CONCLUSION This is the largest study to date assessing stimulant treatment in children and adolescents with ASD, and is the first prospective study quantifying the change over time in the prevalence of treatment with ADHD medications in a population-based national cohort of children and adolescents with ASD. The prevalence of stimulant treatment in youth with ASD of 16% is consistent with earlier studies. The past decade has witnessed a clear and progressive increase in the prescription rates of medications typically used to treat ADHD in children and adolescents in Denmark. This increase is not limited to only those with ADHD, but includes others with neuropsychiatric disorders, including ASD. The risks and benefits of this practice await further study.

The Risk-Return Trade-Off in Human Capital Investment

In this paper we analyze investments in human capital assets in a way which is standard for financial assets, but not (yet) for human capital assets. We study mean-variance plots of human capital assets. We compare the properties of human capital returns using a performance measure and by using tests for mean-variance spanning. A risk-return trade-off is revealed, which is not only related to the length of education but also to the type of education. We identify a range of educations that are efficient in terms of investment goods, and a range of educations that are inefficient, and may be chosen for consumption purposes.

Declining employment success of immigrant males in Sweden: Observed or unobserved characteristics?

Abstract. Focusing on Nordic and Yugoslavian immigrant males, we study the determinants of employment success of natives and immigrants in Sweden. Furthermore, we investigate the reasons behind the arising gap in employment success between Swedes and immigrants from 1970 to 1990. In a decomposition analysis, we find that the main part of the decline in the employment probability of immigrants relative to Swedes over time is explained by a change in coefficients (unobserved characteristics) rather than a change in determinants (observed characteristics).

Effect of drugs on the risk of injuries in children with attention deficit hyperactivity disorder: a prospective cohort study

BACKGROUND Injuries represent the largest disease burden and most common cause of death in children. Attention deficit hyperactivity disorder (ADHD) is associated with increased mortality, with accidents being the most common cause of death in ADHD. However, it is not known whether pharmacological treatment has any modifying effect on the risk of injuries in children and adolescents with ADHD. METHODS Using Danish national registers, we followed a cohort of 710 120 individuals, including 4557 individuals diagnosed with ADHD before age 10 years. Using a quasi-experimental, difference-in-difference design, we estimated the odds ratios (ORs) for injuries and the mean change in prevalence rates of injuries and emergency ward visits before and after treatment, with matched untreated children with ADHD at the same age serving as controls. FINDINGS Children with ADHD were more likely to sustain injuries, compared with children without ADHD, at age 10 years (adjusted OR=1·29, 95% CI 1·22-1·37) and at age 12 years (adjusted OR=1·30, 1·23-1·37). From age 5 to 10 years, the prevalence of injuries in children with ADHD who were treated with ADHD drugs decreased from 19% to 14%, compared with a prevalence of about 17% in non-treated children with ADHD. This corresponded to an adjusted difference-in-difference reduction in prevalence of injuries at age 10 years of 31·5% (8·2-54·8) and 43·5% (18·1-69·0) at age 12 years due to treatment. Pharmacological treatment also reduced the prevalence of emergency ward visits at age 10 years (28·2%, 6·3-50·1) and age 12 years (45·7%, 25·8-65·7). INTERPRETATION Children with ADHD had an increased risk of injuries compared with other children. Treatment with ADHD drugs reduced the risk of injuries by up to 43% and emergency ward visits by up to 45% in children with ADHD. Taken together with previous findings of accidents being the most common cause of death in individuals with ADHD, these results are of major public health importance. FUNDING The Lundbeck Foundation, the Danish Council for Independent Research, Centre For Integrated Register-based Research at Aarhus University, the Region of Southern Denmark Research Foundation, and Wørzners Foundation.

An Economic Analysis of Identity and Career Choice

Standard economic models which focus on pecuniary payoffs cannot explain why there are highly able individuals who choose careers with low pecuniary returns. Therefore, financial incentives are unlikely to be effective in influencing career choices of these individuals. Based on Akerlof and Kranton (2000), we consider a model of career choice and identity where individuals derive non-pecuniary identity payoffs. Using factor analysis on a range of attitude questions, we find two factors related to identity (career orientation and social orientation), which are important for educational choices. The implication is that policymakers and institutions of higher education need to focus on identity related issues rather than just improved financial incentives if they aim at attracting the high ability youth to occupations with excess demand for labor.

Cardiovascular Safety of Stimulants in Children with Attention-Deficit/Hyperactivity Disorder: A Nationwide Prospective Cohort Study

OBJECTIVE The purpose of this study was to determine whether stimulant users are at higher risk of a later cardiovascular event than are non-users, examining this association in both a national cohort and a population-based sample of children and adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD). We also aim to examine a possible dose-response relationship in such an association. METHODS We conducted a longitudinal, prospective cohort study of all children born in Denmark between 1990 and 1999. Within this cohort, children with ADHD were identified. Data from national health registers on psychiatric and somatic diagnoses, stimulant prescriptions, cardiovascular risk factors, pre- and perinatal and sociodemographic covariates in all children and their parents were merged, using the unique personal identification number. Hazard ratios (HR) for cardiovascular events were estimated using Cox regression, adjusted for other known risk factors. RESULTS In the total population (n=714,258 contributing a total of 6,767,982 person-years) use of stimulants increased the risk of a cardiovascular event; adjusted HR=1.83 (1.10-3.04). In children with ADHD (n=8300) stimulant treatment also increased the risk of a cardiovascular event (adjusted HR=2.20 [2.15-2.24]), with a complex time-dependent dose-response relationship. CONCLUSIONS This is the first nationwide cohort study of the cardiovascular safety of stimulants in children and adolescents, and it represents, to our knowledge, the longest prospective follow-up study. Cardiovascular events were rare but twice as likely in stimulant users as in non-users, both in the total national population and in children with ADHD. We found a complex, time- and dose-dependent interrelationship between cardiovascular adverse events and stimulant treatment in children and adolescents. Our results suggest a safety signal with an increased risk of cardiovascular disease associated with stimulant treatment in children and adolescents, even after adjusting for a number of potential confounders.

Child Labor and School Attendance: Two Joint Decisions

In this paper, a variety of potentially explanatory indicators for child labor and school attendance in Zambia is scrutinized. By analysing the results from a bivariate probit model, new doubt is raised with regard to the income sensitivity of the child labor choice. Different factors in the model influence the child labor and schooling choice. Based on the results, sensitization, narrowly targeted subsidies or stipends are suggested to at-risk households in selected provinces, provided that children are sent to school.