When Sarah Meets Lawrence: The Effects of Coeducation on Women's College Major Choices

We leverage variation in the adoption of coeducation by US women's colleges to study how exposure to a mixed-gender collegiate environment affects women's human capital investments. Our event-study analyses of newly collected historical data find a 3.0–3.5 percentage point (30–33 percent) decline in the share of women majoring in STEM fields. While coeducation caused a large influx of male peers and a modest increase in male faculty, we find no evidence that it altered the composition of the female student body or other gender-neutral inputs. Extrapolation of our main estimate suggests that coeducational environments explain 36 percent of the current gender gap in STEM majors.