"Women and men both view sponsorship by senior leaders as essential for success. Yet women report fewer substantive interactions with senior leaders than their male counterparts do—and this gap widens as women and men advance. In the same vein, women are less likely to say that a senior leader outside their direct management chain has helped them get a promotion or challenging new assignment.
This disparity may be caused—or even compounded—by differences in women’s and men’s professional networks. Women are three times more likely to rely on a network that is mostly female. Because men typically hold more senior-level positions, this means women are less likely to get access to people with the clout to open doors for them."
Can't wait for the 2017 study, but if you would like to read the 2016 Women in the Workplace Report by Lean In (McKinsey & Company)