Motivated by a desire to put data behind the anecdotal evidence of high-powered women leaving their professions, a study in this month’s Harvard Business Review has found that women are more likely to have taken time off than men, resulting in their underrepresentation in senior positions.

There are two ways of explaining this phenomenon, said Carolyn Buck Luce, one of the authors of “The Hidden Brain Drain: Off-Ramps and On-Ramps in Women’s Careers.”

“You can either blame the women and say they can’t cut it,” Buck Luce said, “or you can blame the model.”

The study, conducted by the Center for Work-Life Policy and sponsored by Lehman Brothers, Goldman Sachs, and Ernst & Young, surveyed 2,443 women and 653 men in four sectors: law, medicine, finance, and academia. The study has been in progress since early last year.

The study has produced numbers that the authors say relate interestingly to University President Lawrence H. Summers’ stated opinion that discrimination is a lesser factor in explaining the underrepresentation of women in higher education. The study shows that women in academia are less likely to leave their careers for reasons relating to child care than their counterparts in different occupations.

The study found that 45 percent of women overall leave to spend time with their children, but only 21 percent of women in academia cite this as one of their own reasons for leaving.

In fact, 36 percent of women in academia say their careers are not satisfying or enjoyable, compared to only 29 percent of women overall.

Moreover, 33 percent of women in academia say they “felt stalled” in their careers, as opposed to 23 percent generally.

Women overwhelmingly said that personal interaction and recognition were crucial components of the ideal workplace. Building on previous research which found that fewer women considered themselves ambitious than men, the authors of the study argue that there is a correlation.

“To hold onto their dreams, not only must women attain the necessary skills and experience, they must also have their achievements appropriately recognized,” wrote Buck Luce and study co-author Sylvia A. Hewlitt. “To the extent the latter is missing in female careers, ambition is undermined.”

The authors say their data flies in the face of what has been called an “opt-out revolution,” or what was described by Summers as the “high powered job hypothesis.” Women aren’t simply choosing family over work, they say, but are also suffering the effects of an “exclusionary business model,” in which linear commitment to a career is a requirement for admittance into the upper echelons.

Their statistics show that though 93 percent of women who leave say they want to return, they frequently experience difficulty doing so. Even though the average time off is only 2.2 years, women must often switch careers or accept pay cuts in the process of re-entering the work force, the study found.

More revealingly, only five percent of women say they want to return to their previous employers. Twenty-one percent of women felt “there is an unspoken rule at my workplace that people who use [flexible-time] options will not be promoted,” the study said.

The authors argue that it is in companies’ best interests to develop policies that will retain women—or make them willing to return after time away. They say the current “business model” is wracked by inefficiencies, because companies lose people they have trained to their competitors, underutilize available talent, and waste resources finding and training replacements.

“Leaders have to recognize that the traditional male model that was put in place when it was all men in the workplace will not be the one that will fully utilize human talent,” Buck Luce said.

—Staff writer Natalie I. Sherman can be reached at nsherman@fas.harvard.edu.