We shed new light on the effects of having children on hourly wages by exploiting access to data on the entire population of employed same-sex twins in Denmark. Our second contribution is the use of administrative data on absenteeism; the amount of hours off due to holidays and sickness. Our...

This is one of the few studies that estimates the effects of type of childhood care on academic achievement at higher grade levels by linking day care registers and educational registers. We use entire birth cohorts of ethnic Danish children, enrolled in either center based day care or family...

This paper uses register based data covering the entire population of Danish children enrolled in preschool in 2006-2007 to investigate whether the gender composition of preschool staff members affects the timing of school start and subsequent academic performance. To estimate effects of the...

This paper uses Danish register-based data for the population of children born in 1990-1997 to investigate the effects on parents of having a child with attention-deficit/hyperactivity-disorder (ADHD). Ten years after birth, parents of children diagnosed with ADHD have a 75% higher probability...

This paper investigates pre-teenage effects of the choice of type of non-parental child care at age three (preschool relative to more informal family day care). We exploit a Danish panel data child survey merged with administrative records along with a pseudo-experiment that generates variation...

Bullying is a widespread social phenomenon. We show that both children who are being bullied and children who bully suffer in terms of long-term outcomes. We rely on rich survey and register-based data for children born in a region of Denmark during 1990-1992, which allows us to carefully...

We are the first to investigate longer-term effects of pharmacological treatment of ADHD on children's health. We rely on a difference-in-differences strategy while exploiting Danish register-based panel data for children born in 1990-1999. We study effects of treatment initiated between ages...

This paper investigates the effects of school starting age on crime while relying on variation in school starting age induced by administrative rules; we exploit that Danish children typically start first grade in the calendar year they turn seven, which gives rise to a discontinuity in...

This paper estimates effects of early ADHD medication use on key human capital outcomes for children diagnosed with ADHD while using rarely available register based data on diagnoses and prescription drug purchases. Our main identification strategy exploits plausible exogenous assignment of...

This paper estimates how peers' achievement gains are affected by the presence of potentially disruptive and emotionally sensitive children in the school-cohort. We exploit that some children move between schools and thus generate variation in peer composition in the receiving school-cohort. We...