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In America, letters to the editor have been around as long as newspapers. They represent one of the country’s most basic modes of political engagement, accessible—at least in theory—to all. They are also written, overwhelmingly, by men.

Editors I contacted at The Kansas City Star, The Chicago Tribune, The Tampa Bay Times, and The Toronto Star told me that the vast majority of letters come from men. At The Atlantic, we’ve seen the same thing. (Our readership is close to evenly split between genders.) “We are aware of the fact that sometimes our Letters page is dominated by male voices,” Sue Mermelstein, a staff editor in the Letters Department at The New York Times, wrote to the Huffington Post. “This reflects the fact that a large majority of our letter writers are men—why, we’re not sure.”

Now that most journalism happens online, letters to the editor are no longer the only forum for engaging with the media. Many magazines and newspapers have an online comments section, allowing readers to respond—either under their real names or anonymously—at the bottom of each article. (The Atlantic chose to eliminate online comments in February of this year, opting instead for an online Letters section.) Like letters to the editor, these comments also tend to be dominated by men.

The disparity, several experts told me, stems from “the confidence gap,” a phenomenon covered by Katty Kay and Claire Shipman in The Atlantic in 2014. Women are less likely to think that they’re, one, skilled enough write something worthwhile, and, two, able to offer insight other people should care about, Joyce Ehrlinger, assistant professor of psychology at Washington State, said.

For a study she co-authored with Cornell psychologist David Dunning, Ehrlinger gave male and female college students a basic science quiz. Before students took the quiz, Ehrlinger and Dunning asked participants to rate their science ability and, after the quiz, to guess whether they’d gotten each question right. Responding to both questions, women assumed that their science ability was significantly worse than it really was. Men didn’t have that problem. There are hardly any subjects that women approach with more confidence than men, according to Ehrlinger. Cooking, she said, is one of only a handful of exceptions.

[Readers respond: Why Don’t Women Write to the Editor? Because They’re Doing Absolutely Everything Else]

By telling themselves they’re not experts in anything, “women are pulling themselves out of the discussion,” Catherine Orenstein, founder of The Op-Ed Project, an organization devoted to addressing the gender disparity in authorship of op-eds, said. “A lot of them will in some way discount themselves and their knowledge. If you think about it, what it means is that there’s a disconnect between what we know and our sense that it actually matters.” When she participated in a recent workshop sponsored by The Op-Ed Project, Ehrlinger said the coaches spent the majority of the time “convincing people that their perspective was worthy of sharing.”

Taking a science quiz in private is one thing, but writing a letter to the editor in a public forum is another.  Writing in public is a particular challenge, Andrew Perrin, a professor of sociology at the University of North Carolina, Chapel Hill, who studied the demographics of letters to the editor, said. “To read an article online, and decide that whoever else is reading this article ought to have my opinion—that takes a certain degree of self-importance,” Perrin said. Women, he said, are more likely to post an opinion on Facebook, where they have a connection to every person reading it—and where readers, by way of that connection, have more reason to care about their viewpoint.

Perrin distinguished between two different kinds of confidence: “my opinion is correct” and “I am entitled to be heard.” He explained, “In many cases, the confidence men have is not particularly warranted.” Of all the letters submitted to the Greensboro News and Record, a local newspaper in North Carolina, which Perrin reviewed for his study, 90 percent did not explicitly refer to an article published by the paper. “Lots of the letters in our data were literally incoherent,” Perrin told me. “Some of the letters addressed as many as 18 different topics.” Women, Perrin said, are probably even less likely to feel entitled to say something than to think their opinion is correct.

Even if The Op-Ed Project succeeds in making women more confident—helping them overcome social norms to become more sure of their expertise—women would likely face backlash. Studies show that when women are pushy and forceful in their opinions—adjectives that often characterize a good letter to the editor—they probably aren’t going to be very popular. “Let’s be blunt,” Kay and Shipman wrote, she’ll be “labeled a bitch.” Women are also more likely than men to face harassment when they publish their opinions. “Speaking up makes you a target,” Ehrlinger said. So when they consider writing a letter, women have to ask themselves: “Do I want to be that target?”

Women aren’t the only group hesitant to share their opinions in local and national publications. Perrin found that African-Americans are about half as likely to submit letters than people who identify as white. The disparity, he said, comes down to this question: Do you feel like an important member of the public? If you do, you’re a lot more likely to think you have an opinion worth sharing.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.