(CNN Business) Three is a powerful number, especially when it comes to putting women in positions of power.
Within a boardroom, one woman — or even two — isn’t enough to shift a culture, research shows. Although a majority of companies in the S&P 500 have at least one woman on their boards only 25% have more than two, according to a recent study from PwC.
But that’s still not enough, according to Vicki W. Kramer, lead author of “Critical Mass on Corporate Boards.” “The power of three” is the tipping point that brings change to the company culture, she says.
“Three really makes a difference,” she says. “Women said they felt more comfortable and they could be themselves. Often if they’re a single woman, they’re hyper-conscious of not wanting to be pigeonholed. When they have three women, it’s easier to divide that responsibility.”
“As the lone woman, they felt they couldn’t change the culture, even though these are amazingly impressive women,” says Alison M. Konrad, professor at Western University and Kramer’s fellow researcher. “They were contributing, they were making a difference, but the culture of the board is not changing with one.”
One woman on a board is automatically seen as different from her male colleagues, so in some ways attracts more attention (sometimes unwanted attention, like when male members ask “for the women’s perspective”). But without other women to help, many female members also said some men would ignore their contributions or breeze past their comments entirely.
Yet even with two women present, research shows men will still see them as a minority interest.
“Even with two, we heard often of the sense that gender was still much too visible,” Kramer says. One female board member she interviewed said the chair would sometimes confuse her with the other woman on the board. “It was as though they were interchangeable,” Kramer said.
Two women also run the risk of being perceived as “ganging up” on the other male members. One woman told Kramer she made a point of not sitting beside her female colleague, so as not to create the illusion of a “female conspiracy” that would upset male board members.
“When you go to a cocktail party and you don’t know anyone, you’re by yourself,” Zalis says. “But when you bring the buzz with you, a few women with you, you create your own dynamic. No matter how powerful your voice is, you don’t change the dynamic on your own.”
Getting three women on a board isn’t easy, however. Instituting term limits for longstanding members or hiring outside recruitment firms can help, and Zalis suggests boards appoint women in waves.
“When you put one, one, one, you’re quota-filling,” she says. “I think that’s diversity with quota, not diversity with culture.”
The best board members aren’t the obvious pick of the old boys’ network, says Konrad. When presented with a diverse slate of candidates, directors instead gravitate to the potential members “who had to work a lot harder to get to where they are.”
“When people say ‘There aren’t women out there,’ I’d say ‘You didn’t look,'” she says.