The Effects of High School Peers' Gender on College Major, College Performance and Income

Using a newly constructed longitudinal data set of 30,000 Italian individuals, we analyse whether the gender composition of peers in high school affected their choice of college major and labour market outcomes. To identify causation, we exploit random assignment of classmates within school-cohort. We generally do not find significant effects of peer gender on college choice and following outcomes. Only male students graduating from classes with a very large majority of male peers were more likely to choose prevalently male' college majors (Economics, Business and Engineering). This impact, however, was undone by major attrition and did not affect labour market outcomes.