Caren Merrick sits on the boards of five publicly traded companies, as well as the Metropolitan Washington Airports Authority. (Dayna Smith/For The Washington Post)

Despite a widespread push in recent years to add diversity to the boardroom, the Washington area continues to lag behind the rest of the country in its representation of women on corporate boards, according to a report released Thursday.

Women hold 14 percent of board positions at publicly traded companies in Maryland, Virginia and the District, compared with 17.9 percent nationally, according to a study by the Kogod School of Business at American University.

“When you start to look at the boards at Washington’s largest companies, you start to see a cadre of retired executives — and most of them are male,” said Jill Klein, an assistant dean at the Kogod School, who oversaw the report. “Progress has been glacial.”

The percentage of women on local boards inched up from 12.7 percent last year and 10 percent in 2012, according to the Kogod report, commissioned by Women in Technology, a Falls Church-based nonprofit group.

Twenty-five percent of the region’s 250 publicly traded companies do not have women on their boards, down from 52 percent in 2010, the report said. Among them: data analytics firm ­MicroStrategy in Tysons Corner, technology firm ePlus in Herndon and government contractor CACI International in Arlington. The three companies didn’t respond to requests for comment.

Debra L. Lee, chairman and chief executive of BET Networks, also sits on the boards of Marriott International, WGL Holdings and Twitter. (Matt Sayles/Associated Press)

Nationally, 3 percent of companies in the Standard & Poor’s 500-stock index had all-male boards, down from 12 percent in 2008, according to a recent report by the audit and consulting firm PwC.

Diversity on corporate boards has become a hot-button issue in recent years, as shareholder groups and government regulators have put pressure on companies to look beyond white men to a larger pool of possible directors.

Earlier this year, Securities and Exchange Commission Chair Mary Jo White said that boardroom diversity would be a top priority and that the agency may introduce related requirements. A number of countries, including Germany, France and Spain, have quotas requiring companies to appoint a set percentage of women to their boards. Lawmakers in California, Illinois and Massachusetts have passed legislation encouraging similar action.

But changing the status quo is a slow process, said Caren Merrick, an entrepreneur who serves on the boards of five publicly traded local companies. Corporate boards do not have term limits or age restrictions, which means members often remain in their positions for years, if not decades. When a spot does open up, executives are likely to fill it with their peers, who often happen to be other white men, she said.

“The number-one limiting belief is, ‘I don’t know of very many women who are qualified or board-ready,’ ” said Merrick, who is on the board of WashingtonFirst Bankshares and investment firm Gladstone. “That’s just not true: There are a great many amazingly talented and qualified women in this region. Nominating committees are stuck in a very old-school way of thinking.”

Discovery Communications last month appointed the first woman to its board, Susan M. Swain, co-chief executive of ­C-SPAN, after repeated calls from shareholders and activist groups for the Silver Spring-based company to diversify its lineup of 10 white men, all older than 50.

Overall, 39 percent of the region’s companies had one woman on their boards, while 24 percent had two women.

But the goal, Klein says, is to have at least three women on every board. Currently, 9 percent of local companies have three women on their boards, while 2 percent have four.

“One of anything isn’t enough,” said Klein, previously chief information officer of District-based Riggs Bank (now part of PNC Financial Services). “This is not about tokens. It’s about the ability of people from different backgrounds and experiences to work together.”

Studies have shown that even one woman in the boardroom can help steer businesses to higher sales and revenue. But, research shows, a “critical mass” of three or more women in the boardroom makes for a more open and collaborative environment.

“The more women you have on a board, the freer you feel to speak up,” said Debra L. Lee, chair and chief executive of BET Networks, who is also on the boards of Marriott International, WGL Holdings and Twitter. “When you’re the only one, every time you open your mouth, you’re being seen as ‘the woman’ on the board.”

Local companies that have four women on their boards include WGL Holdings — the ­District-based parent company of Washington Gas — as well as Marriott and Lockheed Martin, which are based in Bethesda.

Among companies with three women on their boards: media company Gannett, consulting firm ICF and defense contractor General Dynamics.

“It’s not about check-the-box diversity but about more thoughtfully constructed boards,” said Lyles Carr, senior vice president of the McCormick Group, an Arlington-based ­executive-search consulting firm. “Once that’s your focus, you’ll end up with people who don’t just look like your proverbial golfing buddies.”