Men outpace women by a significant margin when it comes to earning academic honors at Harvard Business School. What’s behind the gap?

( — Is there an academic gender gap at Harvard Business School? Apparently so. A new study has found that proportionally more men than women receive academic honors at Harvard, and that has been the case for many years.

Though women accounted for 36% of Harvard’s 2009 class, only 11% of the school’s Baker Scholars were female, an honor given to students who are in the top 5% of HBS’ graduating class.

Meantime, women in the class of 2009 received only 21% of the first-year honors (awarded to the top 20% of the class) and 22% of the second-year honors.

The gap narrowed only slightly last year for the class of 2010, according to the study. Though women accounted for 38% of the class, only 20% of the Baker Scholars were female. Some 23% of the first-year honors and only 28% of the second-year honors were awarded to female MBA students.

What makes these differences even more striking is that a subsequent study at Harvard found that women place more importance on academics than men and spend significantly more time preparing for class.

Apparently, the issue is not exclusive to Harvard Business School. A recent study by Harvard students found “a similarly marked academic gender gap” at eight peer business schools. “However, there is little to no awareness of the issue at other schools, especially among students,” the study found. “Women’s groups at other schools tend to focus almost exclusively on career-oriented efforts or increasing the percentage of women in the student body.”

Some of those peer schools, which were not identified by name in the study, have 20-plus percentage point gaps between the proportion of female students and the number of women receiving academic honors.

At Harvard, the gender gap first came to light in a story published last year by the student newspaper, The Harbus. ”I read it with shock,” recalls Kat Shaul, then a first-year student. “It was never something I had thought about, and I certainly didn’t expect the gap to be that wide.” The story galvanized a group of five second-year women, including Shaul, to examine the problem in more detail.

Not surprisingly, there was some immediate improvement after the issue gained visibility. For the class of 2011, which is 36% female, 30% of women had won first-year honors — significantly better than the 23% in 2010 or the 21% in 2009. “Some of the awareness around the issue has probably helped everyone — faculty and students — to narrow the gap,” says Andrea Ellwood, another student who was involved in the study.

But the group’s report found other problems. “Our study suggests that men have a better academic experience than women at HBS,” the authors said. “Thus, although women may be nearing parity in average academic performance, they do not view their experience as positively as men do. This is in stark contrast to findings from academic literature on gender and happiness, which show that on average women report greater life satisfaction than men.”

What’s behind the gap? The students discovered that women tend to hang back in classroom discussions — which typically account for half the grades at Harvard. “Women reported significantly less comfort with class participation than men did,” the study found. “Some women may feel less comfortable participating due to their perceived difference in academic and professional backgrounds from their male peers. Additionally, women often struggle to balance social and professional relationships; many women admit to self-editing in the classroom to manage their out-of-classroom image.”

Megan Lesko, who worked on the study, chalks it up to behavioral differences between men and women that she has noticed at Harvard. “Women tend to self-censor themselves a bit more,” says Lesko. “In a class of 90 people with a fast-moving discussion, the person who gets called on is the person who gets his hand up first. Women just tend to take slightly more time to carefully construct what they want to say out loud. That’s challenging. You can very quickly get into this spiral where if you don’t get a comment in today, you need to say something the next class. And you add more and more pressure on yourself to speak. A lot of women fall into that trap.”

Adds Shaul: “It’s scary for anyone in their first year to speak in front of 90 people, but it’s something you’ve got to get over.”

One solution now in place: “Participation workshops” for new women held by faculty and second-year students to encourage more active classroom behavior.

Another possible reason why women feel less comfortable in Harvard classes is that male students are more likely to have technical or business undergraduate degrees and have received slightly higher scores on the Graduate Management Admission Test (GMAT) than women. On the other hand, the researchers found that women have slightly higher undergraduate grade point averages than male students at Harvard.

Although it was left unexamined, the dearth of female business school professors at Harvard is another factor to consider. Currently, only 17 of 93 full professors at HBS are women and only two out of 11 high-level management practice professors at HBS are women. Some 11 of the school’s 45 associate professors are female as well as 16 of Harvard’s 43 assistant professors.

In every professorial category, the percentage of women who teach at HBS is far below the percentage of women enrolled as MBA students. While second-year students who conducted the study were pleased with the improvement in the most recent figures, they plan to keep the pressure on. Before heading off for jobs at McKinsey & Co., Bain, and Colgate-Palmolive CL , they are now recruiting first-year students to take up the cause next year.

They’re sending out the results of their study to the HBS’ Women’s Alumni Board and plan to make presentations before several Harvard alumni clubs. And they expect to form a coalition with other peer schools to raise awareness of the gap on other campuses. “We don’t want the conversation to go away,” says second-year student Monica Belsito, “so we’re making sure this doesn’t end with us.”

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