Intergenerational and Sibling Peer Effects in High School Majors

This paper estimates peer effects both from parents to children and from older to younger siblings in academic fields of study in high school. Despite the importance of family peer effects, causal evidence is scarce due to correlated unobservables and a lack of data. Our setting is Sweden, where admission to oversubscribed majors is determined based on a student’s GPA. Using a regression discontinuity design, we find large intergenerational and sibling peer effects that depend on the gender mix of a dyad. Younger brothers are 25% more likely to choose the major their older brother enrolls in, but 25% less likely to copy their older sister. Younger sisters copy older sisters (18% increase), but not older brothers. Effects vary based on birth spacing and whether a major is gender conforming. Turning to the effect of parental completion of a major, sons are 22% and 18% more likely follow in the footsteps of their fathers and mothers, respectively. In contrast, parents have little effect on their daughters’ choices, except when a mother majors in the male-dominated program of Engineering. Since high school majors have a strong link to future occupation and earnings, these within family spillovers have long-term consequences for intergenerational income mobility and gender wage gaps. Finally, correlations greatly overstate these causal spillover effects, and miss heterogeneity by gender mix