From Notre Dame Research authored by Brandi Klingerman:

“Women who communicate regularly with a female-dominated inner circle are more likely to attain high-ranking leadership positions, according to a new study by the University of Notre Dame and Northwestern University.

Published in the Proceedings of the National Academy of Sciences, the study showed that more than 75 percent of high-ranking women maintained a female-dominated inner circle, or strong ties to two or three women whom they communicated with frequently within their network. For men, the larger their network — regardless of gender makeup — the more likely they are to earn a high-ranking position. Unfortunately, when women have social networks that resemble their male counterparts’, they are more likely to hold low-ranking positions.

“Although both genders benefit from developing large social networks after graduate school, women’s communication patterns, as well as the gender composition of their network, significantly predict their job placement level,” said Nitesh V. Chawla, Frank M. Freimann Professor of Computer Science and Engineering at Notre Dame, director of the Interdisciplinary Center for Network Science and Applications and co-author of the study. ‘The same factors — communication patterns and gender composition of a social network — have no significant effect for men landing high-ranking positions.’”