Even more interesting is one of Volden’s latest papers, which examines how often female legislators are able to advance their priorities. Tallying up legislation on education, health, and housing—issues on which women introduce legislation more frequently than men—he found that women are less likely to see those reforms become law than if a man had advanced an equivalent proposal. “Not only are ‘women’s issues’ brushed aside in Congress, but they’re particularly brushed aside if sponsored by women,” Volden said. “I could imagine that being enormously frustrating.”

What drives these differences between women and men in Congress? This, too, has been hard to pin down. In the NBER paper, Paserman tried to account for each congresswoman’s personal biography and the demographics of her district, eliminating as many factors as possible to nail down the essential differences between men and women.

He admits there are unknown variables. A popular theory posits that since women face a higher barrier to entering politics—in many parts of the country, voters have never elected a woman to Congress—the legislators who fight their way through are more competent and capable than their male counterparts. There’s also a fraught notion that women are biologically more conciliatory, a conclusion that seems rather paternalistic and unmoored from fact.

Kelly Dittmar, a scholar at the Center for American Women and Politics and a political science professor at Rutgers, has reached a conclusion that is also backed by conversations with women in Congress: Women, far more than men, prize results over status. In an oft-cited 2001 survey of American members of Congress, the number one reason to run for office, according to female legislators, is the ability to effect change in society. The number one reason for men? They always wanted to be a politician.

“Women just want to get things done,” Dittmar said. “They’re not in it for the show.”

Dittmar believes Washington’s ineffectiveness has made running for office less appealing to women—they’re reluctant to go through the meat grinder of campaigning if they won’t be able to get anything done. And the academic literature offers some support to that notion. If Republican women have traditionally fared better than Democrats at finding across-the-aisle cosponsors, but are stymied at the committee level when their party is in power, what leverage do they hold in today’s Republican-controlled, hyper-partisan Congress? And if women are consistently more progressive than the men in their party, how will female GOP legislators fend off primary challengers as the party moves right?

These questions haunt Erin Loos Cutraro, the co-founder and CEO of She Should Run, an advocacy group that promotes women’s leadership in government. While there are now more Democratic women serving in the House than ever before, Republicans have seen a decrease in female representation since a peak in 2007.