Women who communicate regularly with a female-dominated inner circle are more likely to attain high-ranking leadership positions, according to a study by Northwestern University and the University of Notre Dame, published recently in the Proceedings of the National Academy of Sciences.

For the study, the researchers reviewed the social and communication networks of more than 700 former graduate students from a top-ranked business school in the United States. Each student in the study had accepted leadership-level positions, which were normalized for industry and region-specific salaries.

The researchers then compared three variables of each student's social network: network centrality, or the size of the social network; the proportion of same-sex contacts; and the number of strong versus weak network ties.

The study shows that women with a high network centrality and a female-dominated inner circle have an expected job placement level 2.5 times greater than women with low network centrality and a male-dominated inner circle. In addition, women are not likely to benefit from adding the best-connected person to their network.

Also, while the male connections might improve access to public information important to job searches and negotiations, female-dominated inner circles can help women gain gender-specific information that is more important in a male-dominated job market.

The study also shows that over 75 percent of high-ranking women maintain a female-dominated inner circle or strong ties to two or three women with whom they communicate frequently.

"In this context, such an inner circle can provide trustworthy, gender-relevant information about job cultures and social support, which are important to women in male-dominated settings," says Yang Yang, a research assistant professor at Northwestern's Kellogg School of Management.