
For their study, the authors matched Swedish Register data on more than 700,000 students attending primary school in Sweden between 1989 and 2002 to those same students’ earnings at age 30.
In their analysis, the authors found that girls whose classmates were predominantly female earned more, on average, than girls whose classmates were predominantly male. For example, changing from a 45 percent female to 55 percent female classroom led to a $354 increase in annual earnings of women at age 30, equating to a 2.7 percent reduction in the gender wage gap. Based on their estimations, the study authors predict that lifetime earnings could be as much as $12,390 more for women exposed to a 10 percent female increase in their early childhood classrooms.
Furthermore, women whose primary school classmates were predominantly female were more likely to go on to high school, study historically male-dominated school subjects, and choose male-dominated occupations in adulthood, leading to overall higher earnings by age 30.
Notably, boys had slightly worse outcomes when their classmates were predominantly female. However, this trend was not evidenced to the same degree as girls’ benefits for learning in predominantly female classrooms.
The study was conducted by scholars at Durham University Business School in England and the University of Basel in Sweden.


