Women comprise roughly 75 percent of the association and nonprofit workforce, but they hold only 45 percent of the top leadership positions, says Carol Vernon, a certified executive coach and principal of Communication Matters. This discrepancy is often attributed to what she calls “a confidence gender gap.”

Women may be equally skilled and competent but lack their male peers’ confidence. “Research shows that confidence correlates just as closely with success as does competence,” Vernon says.

Women, more than men, may “tend to hold back, play smaller and safer, and not contribute as fully as they can,” she says. And they may deflect much-deserved praise when someone recognizes their accomplishments: “Even some of the most successful women don’t take credit for their accomplishments but attribute it to luck or hard work.”

Workplaces were abuzz about women “leaning in” after Facebook Chief Operating Officer Sheryl Sandberg's 2013 book Lean In: Women, Work, and the Will to Lead. But what exactly should women be doing to put themselves in a position to succeed? For starters, Vernon says, women should speak out a lot more and be sure they are communicating what they want.

“If we want a senior-leadership role, we need to communicate it through our words, nonverbal language, and day-to-day actions,” she says.

What are people picking up on from the things women professionals say and do? “We need to be aware of the signals we send when we don't speak up, when we don't learn new things, and when we don't mentor and encourage others to do their best,” Vernon says.

Even some of the most successful women don’t take credit for their accomplishments but attribute it to luck or hard work. —Carol Vernon

To lean in fully, “it's key for us to clarify what we want from our work and personal lives,” she says. “Regardless of what we choose, we need to leverage our strengths, get help from others in the areas we're not strong in, and intentionally and regularly seek out opportunities.”

And the work environment should encourage women to lean in.

“We need our most senior leaders, male and female, to lead workplace cultures that actively support, mentor, and provide opportunities for women at all levels, so that when women do speak up, they do it from a place of competency and show up confidently,” Vernon notes. Women should both seek mentors and find ways to support other women.

Some evidence suggests that millennials will help close the confidence gap. Members of this group—generally defined as people born between 1980 and 1995—think and work differently from previous generations, and they are more educated and more confident. Vernon says she has noticed a shift: “Many of today’s rising women leaders are actively seeking out ways to contribute more to their organizations.”

She adds, “Fifty-one percent of millennial women—compared to 61 percent of millennial men—say they feel they will be able to rise to the top of their respective organizations. Because millennial women will comprise about 25 percent of the global workforce by 2020, this can mean good things for the association community.”