Advocates for equal pay suffered a setback on Wednesday, as Republicans in the House voted against an amendment that would have protected funding for the collection of pay data by the Equal Employment Opportunity Commission.

Last year, the EEOC under President Obama announced it would require private employers with more than 100 workers, and federal contractors with more than 50, to report their employees’ compensation broken down by sex, race, and ethnicity. The requirement, aimed at shedding light on persistent racial and gender disparities in Americans’ pay, was supposed to take effect in March 2018.

The Trump administration blocked the requirement earlier this year but left the door open for the EEOC to resubmit revised pay reporting requirements for review. The appropriations bill currently before the House, however, excludes funding for implementing a new EEOC reporting requirement, which would make it harder for the EEOC to collect pay data even if it eventually reaches a compromise with the administration. So Reps. Rosa DeLauro (D-CT), Lois Frankel (D-FL), and Bobby Scott (D-VA) introduced an amendment to preserve funding for EEOC data collection, but House Republicans defeated it in a vote on Wednesday, 223-192. (An American Civil Liberties Union blog post on the vote offers some context on the EEOC requirement and its history.)

By blocking funding for data collection, the vote today could stall efforts to make sure women and people of color get fair pay for their work. As Abigail Hess of CNBC notes, the EEOC can sue companies it has reason to believe are guilty of pay discrimination. But since many employees don’t know how much their co-workers make, there’s often no way for anyone to know if they’re being discriminated against. The new requirement would have helped the EEOC spot discrimination; without data broken out by race and sex, its job remains that much more difficult.

Why pay data matters

As Vox’s Sarah Kliff explains, we often talk about “the wage gap” as a single entity, but there are many different wage gaps. In 2016, Asian-American women made about 88 cents for every dollar white men made, while white women made 79 cents, black women made 62 cents, and Hispanic women made 57 cents. Black and Hispanic men also make less than white men, on average, while Asian-American men make a bit more. These disparities also vary by state and by occupation — some jobs have smaller wage gaps than others.

While the wage gap in some occupations is shrinking — women pharmacists, for instance, are doing much better than they used to — pay inequality overall has been slow to change. At the current rate, women overall will reach parity with men in 2059, according to the Institute for Women’s Policy Research. For black women, and for women living in North Dakota, Utah, Wyoming, and Louisiana, the gap won’t close until the 22nd century. For Hispanic women, it won’t close until the 23rd.

To help American workers see pay equity in their lifetime, it helps to have accurate data on who’s making what. “The Equal Pay Data Collection, which would only impact employers with 100 employees or more, encourages companies to identify and correct pay disparities and enables the EEOC to more effectively root out discrimination,” said DeLauro in a statement to Vox. “We need to address pay discrimination head on — not sweep it under the rug.”

But the Trump administration and some business groups have argued that the reporting requirement put too great a burden on companies and wouldn’t help close the wage gap anyway. On Wednesday, the House sided with them.

Correction: An earlier version of this article stated that Republicans defeated the amendment in a party-line vote. While no Democrats voted against the amendment, three Republicans voted for it.