Women gained a handful of director seats at the region's Top 50 public companies this year, but the region's corporations as a whole remain slow to let females into their corporate board rooms.

		Top 50 rankings • See the rankings for this year's Top 50 in Business report.

Three companies from last year's list added women directors: L.B. Foster and Nova Chemicals, both of which boosted their numbers from one to two women; and Matthews International, which added one woman to a board formerly composed of all men.

"It is a positive sign to see local companies that had one woman add another to their board in the past year," said Heather Arnet, executive director of the Women and Girls Foundation, whose mission includes promoting female representation on boards.

Of the 50 largest public companies in the Pittsburgh area, 15 have no women on their boards.

"Our intention with this campaign has not been to say one is enough, but rather to say that zero is unacceptable and bad for business," said Ms. Arnet. "A company with zero women serving on the board is losing a key competitive advantage."

Ms. Arnet cited a variety of research that found companies with more women on their boards perform better. The research was conducted by Catalyst, a New York-based group that focuses on women in business; the Richard Ivey School of Business in London, Ontario; and Wellesley Centers for Women at Wellesley College, Wellesley, Mass.

"A decade's worth of data confirms that the number of women on a board makes a difference and has an immediate impact on corporate performance," Ms. Arnet said.

Catalyst, for instance, reported in 2007 that boards with the most women outperformed boards with the least women by 53 percent in return on equity and 66 percent in return on investment capital.

Catalyst also found that companies with female board members were more likely to hire women for senior management jobs.

In its most recent study of the Fortune 500's corporate boards conducted last year, Catalyst found women comprised about 15 percent of directors' positions while women represented 46 percent of the U.S. labor force.

In the Pittsburgh area, Allegheny Valley Bancorp had the highest percentage of women on its board with three out of eight directors, or 37.5 percent.

Next highest was L.B. Foster with two female directors of a total seven, or 28.5 percent.

At EQT, formerly Equitable Resources, and First Commonwealth Financial, women comprise 25 percent of the boa rds or three positions of a total 12. Others with 20 percent or more were HFF, Allegheny Technologies, PPG Industries and Allegheny Energy.