In the lead up to Equal Pay Day this month, supporters of more federal pay regulations promoted myths about the pay gap between men and women.

In "Time to Pass the Paycheck Fairness Act," Kathy Kelley falsely claimed on April 9 that "on average, Virginia women make 80 percent of a man’s wage in the same job." Kelley is the head of the Richmond chapter of the American Association of University Women (AAUW).

Her claim was untrue, because the 80 percent figure does not compare people working in the "same job." Instead, it compares all women and men in Virginia with "a full-time job," regardless of the job, as even backers of the proposed Paycheck Fairness Act have noted. Different jobs often have very different pay scales for reasons having nothing to do with sexism. On average, male workers have more years of work experience than female workers, who are more likely to leave the workforce to care for children. Moreover, even among full-time workers, males work longer hours, on average, and are more likely to work overtime.

The AAUW has previously made similar false claims about a pay gap for men and women performing “the same job.” On April 10, 2015, its executive director, Linda D. Hallman, sent a mass email falsely claiming "women have to work almost four months longer than men do to earn the same amount of money for doing the same job."

This claim was based on an obsolete and misleading statistic that women made 77 percent as much as men do. But as former Labor Department chief economist Diana Furchtgott-Roth noted in 2013:

The 77 percent figure is bogus because it averages all full-time women, no matter what education and profession, with all full-time men. Even with such averaging, the latest Labor Department figures show that women working full-time make 81 percent of full-time men’s wages. For men and women who work 40 hours weekly, the ratio is 88 percent.

As Washington Post fact-checker Glenn Kessler observed in February 2013, government data show women work fewer hours than men, which explains part of the apparent pay gap:

[S]ince women in general work fewer hours than men in a year, the statistics [such as this one] used by the White House [to push for passage of the proposed Paycheck Fairness Act, discussed at this link] may be less reliable for examining the key focus of the legislation — wage discrimination.

Family responsibilities also play a role. Furchtgott-Roth cites a 2005 study that found: “There is no gender gap in wages among men and women with similar family roles.” In addition to being more likely to seek part-time work, women are also more likely to have gaps in their employment history and to enter lower-paying fields, she notes; and “a 2009 report for the Labor Department found that these factors account for most of the pay gap.”

The AAUW also made a false claim in 2015 about the proposed Paycheck Fairness Act, legislation backed by President Obama that would greatly expand federal regulation of how employers set pay, including making it harder to use legitimate factors "other than" sex in setting pay, as I explain in this law journal article.

The AAUW claimed the Paycheck Fairness Act would just “update the Equal Pay Act of 1963, finally bringing the law in line with the nation’s other civil rights laws.” But in reality, as we noted earlier, the bill is more radical. It would mandate things that courts have never considered appropriate under federal civil-rights laws, like allowing recovery of unlimited emotional-distress and punitive damages even for unintentional violations.