Pietro Campa

Job Market Paper

No Kid Is an Island: Peer Effects and Intergenerational Mobility

Recipient of the Young Economist Award at the Austrian Economic Association Meeting 2026.

How much, and how, do social interactions shape intergenerational mobility? Exploiting within-school variation in schoolmates’ parental backgrounds among Danish high-school students, I show that a $1 increase in average peers’ parental earnings raises annual adult earnings by $0.10. Combined with limited sorting between Danish high schools, this effect drives 3.6% of the difference in adult earnings between children from the top and bottom tercile of the parental earnings distribution. Increasing sorting to the rate observed among U.S. census tracts, the same contribution would be 11.2%. Employment trajectories reveal a key mechanism: as former schoolmates’ careers advance, they facilitate access to higher-paying firms. A formal mediation analysis exploiting peers’ promotion timing shows that improved access to higher-paying jobs accounts for 13% of the returns to exposure. Peer exposure emerges as a determinant of intergenerational mobility, shaping access to opportunities besides individual productivity.