Homophily, Biased Attention, and the Gender Gap in Science

How does homophilous collaboration influence women's early career progress? To answer this question, we turn to a granular dataset of 3,233 highly qualified junior life scientists who receive mentored, early career sponsorship from the National Institutes of Health (NIH) and analyze their publication trajectories as careers unfold. Employing a matched sample approach that exploits variance in the sets of research contacts the junior scientists start out with, we distinguish sex differences in collaboration choices from potential differences in collaboration opportunities. We document that outsized gender homophily among women exists and primarily stems from how female leaders of scientific projects assemble their teams. Women continue same-sex collaborations as lead authors at twice the rate compared to men, on average, and in particular when the mentor is part of the author team or when the focal junior scientist leads the team. As such, systematic gender homophily among female scientists may engender the sponsorship and resources needed to motivate young women to join and pursue an academic career. On the flip side, we show that author teams led by women receive 11% less citations, on average, and up to 29% less citations for work of comparable caliber published in the most influential journals. Taken together, while women's propensity to working with other women may support early career researchers, biased attention to women's work may harm careers and, in particular, women who publish in the highest-impact journals and who would otherwise be poised to narrowing gender gaps at more senior career stages