This paper provides evidence that a lack of accurate information among undergraduate students contributes to the gender gap in student enrolment in Science, Technology, Engineering, and Mathematics (STEM) programs in universities. Specifically, undergraduates in STEM courses tend to underestimate their relative course ranking, suggesting that they are underconfident. Female students are more underconfident than male students.
Conducting a survey at a leading Canadian university, I find that majority of the undergraduate students taking a required first-year calculus course for STEM majors underestimate their relative course ranking, with female students being more likely to underestimate their ranking. This suggests that women are less confident about their relative performance. Additionally, I find that while students are aware of the existence of a wage gap between graduates in STEM and non-STEM majors, both female and male students typically overestimate this gap. In a follow-up randomized experiment, I provide treated participants with information about their relative course rankings, about the fact that female students tend to be less confident according to high-quality academic research, and about expected future incomes for STEM and non-STEM majors. I find that this information treatment led 92% of treated students to update their beliefs. Furthermore, the treated students became more likely to choose a STEM major. These effects are largely driven by female students: treated female students are 17.3% more likely to choose a STEM major and the results are statistically significant at the 1% level, whereas no statistically significant treatment effect is found on the STEM enrolment for male students.