By NICHOLAS D. KRISTOF

Twitter is on schedule to go public as a company next month, a sparkling symbol of innovation, technology — and stale, old thinking reflected in a board of seven white men.

Twitter users are reportedly more likely to be female, so it’s bizarre to have no women on the board. But the main reason to add women — not just on Twitter’s board, but in politics, business and the news media — isn’t just equity. This shouldn’t be seen as a favor to women but as a step that would be good for all of us.

In business, there’s abundant evidence that inclusion of women in senior positions is linked to better results. Catalyst, a research organization, found that the companies with the most women board directors earned a 26 percent higher return on invested capital than the companies with the least women.

Likewise, McKinsey & Company found that the international companies with more women on their corporate boards far outperformed the average company in return on equity and other measures. Operating profit was 56 percent higher.

This isn’t just about boardrooms, though. In the recent government shutdown debacle, some of the first efforts at hammering out a deal to end the crisis came from a group of women in the Senate who were disheartened by the political paralysis. Time magazine’s headline online was: “Women Are the Only Adults Left in Washington.”

That’s progress: The Senate built a restroom off the floor for female members only in 1993, and now, a couple decades later, women are providing adult supervision in the “old boys’ club.”

Still, there’s a long way to go.

The World Economic Forum plans to release its annual Global Gender Gap Report on Thursday, and the United States ranks an embarrassing 23rd out of 136 countries in the status of women. The United States has actually slipped one slot since a year ago and does particularly poorly by international standards in wage equality and in numbers of women in the legislative branch.

Hard-nosed business executives seem to get that this is more than a social justice issue. In a survey by Spencer Stuart, the executive search firm, and Corporate Board Member, a company that researches corporate boards, four out of five board members said that they believed that boardroom diversity “generally results in increased value for shareholders.”

Yet of Fortune 500 companies, roughly 18 percent of board members are female. At this rate, it’ll be after 2050 before women hold half of board seats.

So what do women bring to the board table?

Scholarly research suggests that the best problem-solving doesn’t come from a group of the best individual problem-solvers, but from a diverse team whose members complement each other. That’s an argument for leadership that is varied in every way — in gender, race, economic background and ideology.

Another reason companies with senior women may thrive might have little to do with gender. The promotion of women may just be a proxy for those companies that are most open-minded and forward-looking, and those perhaps are the qualities that are mainly driving profits.

Companies sometimes protest that they can’t find qualified women. Rosabeth Moss Kanter, a professor at Harvard Business School, said that the real problem is boards trying to replicate themselves and that plenty of women would add value to the Twitter board.

“I could come up with 30 names without thinking too hard,” she said, adding that the challenge is to “look more broadly for talent, and be more welcoming to people not identical to those in power.”

And, sorry, Twitter, but how about adding not just one woman to your board, but three? Research suggests that what matters is having a critical mass of about 30 percent women. In Twitter’s case, if it added three women, its board would still have as many men named Peter as it had women.

I also realize that I live in a glass house, because my world of punditry is a cacophony of mostly white male voices. Gender imbalance isn’t just Twitter’s problem, but a global challenge across many sectors.

In the midst of the 2008 economic cataclysm, there was introspection about whether the overwhelmingly male leadership in finance led to a macho culture of excessive risk-taking. A British study found that trading behavior reflected testosterone levels in employees’ saliva: The more testosterone, the more risky the trades.

So would it all have been different if it had been Lehman Sisters?

Maybe not: Lehman Sisters, equally nondiverse, might also have been prone to herd behavior of a different kind. The smart bet would have been on an inclusive and diverse Lehman Brothers & Sisters — and there’s a lesson there for Twitter, for our government, and for all of us.