Nevertheless She Persisted? Gender Peer Effects in Doctoral STEM Programs.

We study the effects of peer gender composition in STEM doctoral programs on persistence and degree completion. Leveraging unique new data and quasi-random variation in gender composition across cohorts within programs, we show that women entering cohorts with no female peers are 11.7pp less likely to graduate within 6 years than their male counterparts. A 1 sd increase in the percentage of female students differentially increases women's probability of on-time graduation by 4.4pp. These gender peer effects function primarily through changes in the probability of dropping out in the first year of a Ph.D. program.