Though companies now invest heavily in mentoring and developing their best female talent, all that attention doesn’t translate into promotions. A Catalyst survey of over 4,000 high potentials shows that more women than men have mentors—yet women are paid $4,600 less in their first post-MBA jobs, hold lower-level positions, and feel less career satisfaction.

To better understand why, the authors conducted in-depth interviews with 40 participants in a mentoring program at a large multinational. All mentoring is not created equal, they discovered. Only sponsorship involves advocacy for advancement. The interviews and survey alike indicate that, compared with their male peers, high-potential women are overmentored, undersponsored, and not advancing in their organizations. Without sponsorship, women not only are less likely than men to be appointed to top roles but may also be more reluctant to go for them.

Organizations such as Deutsche Bank, Unilever, Sodexo, and IBM Europe have established sponsorship programs to facilitate the promotion of high-potential women. Programs that get results clarify and communicate their goals, match sponsors and mentees on the basis of those goals, coordinate corporate and regional efforts, train sponsors, and hold those sponsors accountable.