Imagine a workplace where everyone clocked in at 9 a.m. and was paid the same day’s wage for the work they did – but the men could get their pay for the day at 3:20 p.m. and leave, while the women had to stay on the job until 5 p.m. to get the same check the men got an hour and 40 minutes earlier.

That’s another way to think of the gender wage gap – with women earning on average only 79 cents for each dollar a man earns – that Equal Pay Day, April 12, is intended to highlight. The“79 percent clock” is being promoted by the National Partnership for Women and Families and MTV as a way to dramatize that wage inequity. If you are a woman, you can enter the start and end of your workday and the calculator will “show you when 79 percent of your day has passed and you (or your female colleagues) are no longer being paid.”

For an eight-hour workday that starts at 9 a.m., that moment is generally 3:20 p.m. But that’s an average; for women of color, the moment at which a woman is no longer compensated for her day could be as early as 1:24 p.m. for Hispanics or as late as 3:44 p.m. for Asian Americans. For unmarried women, that moment comes at 1:48 p.m. – 60 percent of the day – the same moment as African-American women, according to a report released this week by the Voter Participation Data Center that also includes state-by-state data for unmarried women.

Of course, if we could see men and women leaving workplaces at different hours because they weren’t equally compensated for the work they did, there would be less opportunity for denying that the wage gap is real. But salary information is usually confidential, especially in mid-level jobs and above. Often, women who are being unfairly paid for their work don’t even realize they are being discriminated against.

When discrimination is documented, we get, particularly from conservative and Republican politicians, the usual round of denials and excuses. Comments from the 2016 Republican presidential candidates are typical: “You’re gonna make the same if you do as good a job,” said Donald Trump in 2015, who has also said that determining whether a man and a woman is doing “the same job” is “a very, very tricky question.” Ted Cruz as a senator voted to block a vote on the Paycheck Fairness Act and has dismissed equal pay legislation as “just empowering trial lawyers to file lawsuits.” (Yes, that’s what lawyers do when laws are violated and people are harmed as a result, but I digress.) John Kasich suggested in 2015 that gender pay disparities are “all tied up in skills” and experience.

The Center for American Progress has published “The Top 10 Facts About the Gender Wage Gap,” and several of those facts address the myths perpetuated by the Republican presidential candidates. The wage gap is real, it does appear among men and women with the same education and experience doing similar jobs, and, according to the CAP fact sheet, “38 percent of the gap is unexplainable by measurable factors,” such as women being concentrated in certain lower-wage occupations or being more likely to have to take unpaid leave to care for family members.

Having Congress pass the Paycheck Fairness Act would go a long way toward reinforcing the already existing Equal Pay Act and getting at the root of gender pay discrimination. A key requirement in the law would be that employers would have to disclose pay information to the federal government based on race, sex and national origin. That would make it easier for the government and individual employees to hold employers accountable for violations of the equal pay laws that already exist but are regularly evaded.

Presidential candidate Hillary Clinton highlighted her support of the Paycheck Fairness Act atan event sponsored by Glassdoor.com, where she praised Silicon Valley firms like Salesforce and retailers like Gap for succeeding in closing the gender pay gap in their companies.

Bernie Sanders has likewise been a longtime supporter of the Paycheck Fairness Act, including it as the first item of his 10-point women’s rights agenda.

Like the “79 percent clock” that rings an alarm when a person has reached 79 percent of their work day, the Paycheck Fairness Act allows for an alarm bell to ring when workers are not receiving equal pay for equal work. It would bring pay inequities into the light of day, instead of the darkness in which Republican presidential candidates would rather have this issue continue to fester.

This blog originally appeared at OurFuture.org on April 12, 2016. Reprinted with permission.

Isaiah J. Poole worked at Campaign for America’s Future. He attended Pennsylvania State University and lives inWashington, DC.