The Committee on House Life voted to balance the sexes in upper class houses by tightening gender restrictions in the housing lottery.

Requiring that houses maintain a proportion of men to women that is within 0.3 of the College mean ratio, the committee voted Thursday to shrink the acceptable range.

In tightening the limit, administrators said they hoped to narrow the disparities that exist in some houses.

"It's going to allow us to narrow the ratio of men to women from some of the highs that we've had," said Catherine M. Millet, housing officer for the College.

Previously, the lottery had operated under a 0.5 restriction on the ratios.

But Millet said the new restrictions will not substantially increase the number of students who are randomized.

"You're putting down one of four choices, so you're still getting one of the four," she said.

Although numbers vary each year, certain houses sometimes attracted disproportional numbers of men or women.

Mather House, for instance, consistently attracted a higher proportion of men to women.

According to records from the Office of Housing, the house presently has two men to every woman.

While Mather's incoming sophomore class last year fell within the accepted range, its senior class displayed a grossly disproportionate ratio of 2.4 men to every woman.

Administrators attribute such differences to intercollegiate and interhouse transfers, as well as students who take leaves of absence.

But Millet said the imbalance does not necessarily mean that many women are leaving the house.

"It doesn't have to be a large exodus. It only takes a few people transferring to change the ratio," she said.

And Winthrop House Master James A. Davis said differences in gender ratios are often the result of random chance.

"We're talking about very small numbers," Davis said. "Small fluctuations can produce a big effect."

In Winthrop House, the senior class has 2.3 men to each woman while the junior class has more women than men, a ratio of 0.8 men to each woman.

Davis said he does not believe that students transfer out of houses because of perceived gender imbalances.

"I don't think there's a difference in attrition by gender," he said.