According to a report released yesterday by New York-based Catalyst, a group that promotes diversity in the workplace, companies with more women board members achieved better financial results than those with fewer female directors.

The report showed that return on equity at Fortune 500 companies with the most female board members was 53 percent higher than it was at companies with the fewest women directors. (Return on equity, a company’s after-tax income divided by book value, is a measure of how well earnings are reinvested).

“What it means is that women need to be in the boardroom,� said Ilene H. Lang, president of Catalyst, a nonprofit research firm that focuses on expanding the opportunities for women in business.

Lang said, the relationship between female board members and a company’s financial success “is not cause-and-effect, but there’s a very strong link.”

Rosa Bennett, president of R.B. Search Services Inc., a Spring Valley employment-services firm, said she wasn’t surprised by the study, but added that women on boards needed to be vocal in order to actually influence a company.

Bennett, who also serves on several private business and nonprofit boards, said today,

My voice is heard if I speak loud enough. I have to be intentional. If not, I will just be looked over … Because women can be in the boardrooms and they can be silent They need to make a difference, they’re not just sitting there to fill a seat, they’re there to make changes.

In the survey, Catalyst divided Fortune 500 companies into four quarters by percentage of women on their boards of directors, then looked at their financial performance.

The group of companies with the highest average percentage of women directors did better. Their average return on equity was 14 percent.

That group included JPMorgan Chase & Co., Merrill Lynch & Co., Bank of America Corp., Exxon Mobil Corp., Walt Disney Co. and General Electric Co. At least 17 percent of board members at each of those 132 companies were women.

In the lowest-scoring group of 129 companies, the average return on equity was 9.1 percent. Each of those companies had fewer than 8.3 percent of women directors, Catalyst said.

That group included Citigroup Inc., Bear Stearns Cos., General Motors Corp., Apple Inc., Time Warner Inc., Capital One Financial Corp. and Countrywide Financial Corp.

Return on sales was 42 percent higher for the top group than for the group with the fewest women directors, the study said, dividing those companies’ pretax income by their total sales.

The survey was taken using financial data from 2001 to 2004 of 520 companies that were in the Fortune 500 during that time. Those years were chosen because the U.S. economy was stable, the group said.

Bloomberg News contributed to this report.