Employers need flexible path for women.

LAWRENCE Summers, the president of Harvard, recently created a stir by wondering out loud whether women's brains are wired for math and science. Almost lost in the resulting din was one primary reason he gave for women being underrepresented in tenured positions in math and science.

Summers offered the "high-powered" job syndrome as a major reason why few women measure up. Due to family pressures, among other things, most women are simply unable to clock 80-hour work weeks. His comments add fuel to the "Opt-Out Revolution" debate--essentially, whether women are less committed to their careers than men.

Sylvia Ann Hewlett and I present a different reality. Women want to work, and corporations must find alternative pathways to power. Our study, based on a sample of nearly 2,500 highly qualified women, examines the realities of women's challenges and choices, probes their ambition, and traces the course of their careers.

Our research shows beyond question that highly qualified women want to work. Not only have they invested heavily in their education and careers, but their professions give shape and meaning to their lives. Of the women who have taken an "oft-ramp" from work, a full 93 percent want to come back.

And many do take off-ramps. Nearly 60 percent of the women we surveyed take time out from their careers (37 percent) or follow what we call a "scenic route." They decline a promotion, transfer from line to staff roles, take a job with less responsibility or work part-time, all in order to be able to manage the other responsibilities in their fives from time to time, be they children (45 percent), elder care (24 percent) or other outside interests. Put another way, the majority of highly qualified women have non-linear careers.

This places women at odds with the customary linear progression of their male counterparts, who progress up the career ladder in lock step and thereby create the norms of the traditional career path.

Women pay a large price for their choices. Though the average time out is short (2.2 years--only 1.5 years for women in banking and finance), highly qualified women lose across the board, in opportunity, access, responsibility and remuneration. Of those who come back to work, only 74 percent find jobs, and only 40 percent come back full time.

These "on-rampers" suffer financially--experiencing an 11 percent decrease in salary after one year out--rising to 37 percent if their off-ramp is three or more years. Without the necessary training, support, role models and mentors, many women who do make it back are lost on reentry.

The corporations suffer as well. Over the next decade, companies will again be facing a labor shortage as the baby boomers begin to retire. Furthermore, the U.S. Department of Education projects that over the next decade, women with advanced or professional degrees will increase by 16 percent while their male counterparts will increase by only 1.3 percent. Most alarming of all, a full 95 percent of the women in our survey who took an off-ramp would not return to their previous employer.

The first generation of equal opportunity practices in the workplace, which dealt primarily with access, has been relatively effective. Today, 58 percent of undergraduates are women. But whether due to Glass Ceilings, Brick Walls or Unmarked Paths, progress has stalled--highly qualified women are languishing.

The corporations who will win in the future are those that make a significant push to adopt a second generation of policies and practices that focus on tapping into the manifold talents and skills of highly qualified women. This will require a concerted effort to transform the pathways to power so as to better align with the realities of women's lives. This effort will bring great rewards to the women--and men--who are the keys to success for companies and institutions.

Let me close with a modest suggestion. Summers and corporate leaders like him might begin by blaming outdated work models, not the women who can't or won't work 80 hours a week. There are many progressive companies, big and small, that have taken this imperative to heart. Among them are the 19 global companies that form the Hidden Brain Drain Task Force and which sponsored our research. Many new pathways to power and a rich menu of on-ramps are being developed. Those companies who say it cannot be done will discover the hard way that this year's failure of imagination will start showing up on next year's bottom fine.

Carolyn Buck Luce, a senior leader in the Global Accounts Group at Ernst & Young LLP, is coauthor of "Off-Ramps and On-Ramps: Keeping Talented Women on the Road to Success," which appeared in the March issue of the Harvard Business Review.