To get a great job, you’ve got to network—make contacts, know the right people. You know the drill. But a study out today in the Proceedings of the National Academy of Sciences suggests that the kind of networking that works best for men isn’t enough for women.

Women need access to key kinds of information that men don’t. And how can they get it? From other women.

The study looked specifically at graduates of a prestigious MBA program, using these students' emails to map out their social networks. (The program is not named in the study to protect student privacy.) For both men and women in the program, landing highly ranked leadership positions was correlated with having “high centrality” in their peer network, meaning they are connected to other well-connected peers across their social network. These kinds of contacts provide helpful information for job seekers, like who’s hiring, what salaries look like, and what a company’s reputation is. But the researchers found that high-placing women shared an additional characteristic: In addition to high centrality that would give them access to general job information, they also had a tight-knit inner circle of other well-connected women.

That tight-knit circle of other women provides a crucial benefit to women job seekers—what the authors of the study refer to as “gender-specific private information and support.” That means insight into questions such as the following: Does this company treat women well? Are women leaders respected? Is this a hostile work environment? Is the company looking to increase its gender diversity? The study authors hypothesize that the answers to these questions help women apply to jobs that better fit them, tailor their interviews to the work culture, and negotiate better. Men, conversely, don’t need to worry so much about whether a potential new job will be a hostile or supportive fit because of their gender.

“Quite frankly, most of the jobs are still male-dominated and therefore the kind of private information that's so important to help women get ahead isn't as important to men's advancement,” says Northwestern University Kellogg School of Management data scientist Brian Uzzi, the lead author on the study.

Of the top Fortune 500 companies, only 25 had women CEOs as of 2018, a meager 5 percent. Women in male-dominated fields face all sorts of hurdles, not just in breaking into positions of power, but also once they attain them. Women make less than men in their same positions, face bias around motherhood and maternity leave, and are often asked to do more “feminine” tasks (such as service or secretarial work) unrelated to their actual job, among other gender inequities.

“Women have to work smarter. Women have to pay more attention [than men do] to connecting to people whose third-party contacts are otherwise not connected to them already.” Brian Uzzi, Northwestern University

Uzzi and his coauthors analyzed the peer networks and job placements of the 728 students, representing two class years, who graduated from the MBA program in 2006 and 2007—all of whom landed leadership jobs, so the researchers ranked the positions according to prestige and other factors. Of those students, 542 were men and 186 were women, which is roughly consistent with the researchers’ findings that women make up about a quarter of business school students nationwide.

The researchers had deep access to the students’ information, and used it to try to reconstruct their social networks. They did this by looking at the students’ emails with one another—more than 4.5 million messages total. (Apparently back in in the aughts, MBA grads mostly communicated via email.) The emails were all anonymized and stripped of their content. But by looking at who was emailing each other and how often, they could map out the connections and how strong they were.

They also had access to anonymized students records, so they could factor in GPA differences, job experience, and other relevant info. In addition, they conducted informal interviews with the students.

What they found was that men with meaningful connections to influential peers across the student body were 1.5 times more likely to be hired in a highly ranked leadership position after graduation, compared with men who were less well connected to their peers. Women with the same kind of strong connections across the student body didn’t fare as well. The women who landed the best jobs tended to have both strong connections to the student body and a tighter inner circle of at least two or three women.