Mentors and mentees should heed the sacrosanct 70-20-10 rule.

By Herminia Ibarra (Contributor, Harvard Business Review)

A new McKinsey study reports statistically what we already knew from personal experience: that mid-career and senior women tend to be found disproportionally in staff jobs, or “pink ghettos,” relative to men.

The report tells us that 50% to 65% of women at the vice-president level and higher are in staff roles, compared with only 41% to 48% of men, who are more likely to be in the line jobs that lead to the top.

This subtler gender gap — one that is difficult to detect when companies only count the total number of men and women at each grade level — is the primary reason we still find so few women in the C-suite (19% in the U.S., according to the same McKinsey report).

To tackle the disproportion, most companies offer mentoring programs, networking among women, and women’s leadership programs focusing on topics like self-promotion and personal branding. These rarely work, and they breed cynicism.

What should they do instead? Follow the 70-20-10 rule.

» Read the full article on Harvard Business Review.