When Philadelphia city officials went to federal court in March fighting for a law that bans employers from asking job candidates about their salary history as a way to address pay inequity, one judge’s line of questioning was simple: How do we know this will work?

“That’s what legislatures do,” city solicitor Marcel S. Pratt responded. “They try measures based on the evidence, and if something doesn’t work, then they tweak it.”

That’s the situation for many lawmakers across the country as they attempt to tackle the gender wage gap: trying new measures and seeing what sticks. (Federal labor data show that women, on average, make about 82 cents for every dollar their male counterparts make, a rate that’s been largely unchanged for the last decade. Women of color make less.)

Tuesday is Equal Pay Day, which marks how far into the year women must work to earn what men did in the previous year, and legislation is moving this week in Harrisburg, Trenton and Washington. On Thursday, the U.S. House passed the Paycheck Fairness Act, which would make it harder for employers to justify gender-based pay disparities. Seven Republicans, including Pa. Rep. Brian Fitzpatrick, joined Democrats in passing the legislation, though the bill’s path in the Senate is uncertain.

Here’s a look at what policymakers in Pennsylvania and New Jersey are doing — and not doing — to address the wage gap:

Salary-history bans

Philadelphia City Council in 2017 passed a bill making the city one of the first jurisdictions in the country to ban employers from asking job candidates about wage history. The idea is that inequities are passed on from employer to employer when pay is based on past salary.

The law’s fate is uncertain — the U.S. Third Circuit Court of Appeals is currently weighing whether the ban violates the free speech rights of employers, as the Greater Philadelphia Chamber of Commerce has argued.

In the meantime, salary-history bans have become the regulation du jour for governments looking to take a whack at the wage gap. Eight states and six municipalities have passed salary-history bans for all employers, and four states, including Pennsylvania and New Jersey, used executive orders to bar government agencies from asking about past salary.

Last week, the New Jersey Assembly passed a salary-history ban that would apply to all employers. The bill now goes to the state Senate and could be taken up by the body’s Labor Committee as early as May, according to Assemblywoman Joann Downey (D., Monmouth), the bill’s sponsor.

Lawmakers in Harrisburg have introduced similar legislation, though Democrats say they are doubtful that such a bill would pass while the legislature was under GOP control. Rep. Donna Bullock (D., Phila.) said the legislature needs more women before it’s likely to meaningfully address the wage gap.

The state Senate in 2017 did pass a pay equity bill, but it included a preemption provision barring municipalities from instituting their own salary-history bans and could have nullified Philadelphia’s law. The bill died in the House.

“Preemption is a real threat,” said Amal Bass, staff attorney at the Women’s Law Project, “and it really is taking away from municipalities their ability to respond to the needs of their constituents.”

The future of salary-history bans could be decided by the courts before that happens. Last May, a U.S. District judge halted the provision in Philadelphia’s law that prohibits employers from asking about salary history but he agreed the government could bar employers from actually using that history to set wages. Both the chamber and the city appealed.

Attorneys for the chamber say because it’s attempting to restrict speech, the city must prove the ban will actually reduce the wage gap. The city says that data don’t exist because it’s a new approach.

Experts say it’s common sense that basing a person’s salary on a previous wage will perpetuate inequities that data show exist for women and people of color, according to Pamela Coukos, CEO of Working Ideal, a Washington-based firm that consults companies and local governments on pay equity.

Employers should instead use market research and the duties of the job to create a pay scale for a position regardless of the candidate, said Deborah Vagins, senior vice president of public policy and research at the American Association of University Women.

Updates to state equal pay laws

Last year, New Jersey Gov. Phil Murphy signed a package of legislation that overhauled the state’s equal pay law by:

  • Extending equal pay protections to all protected classes.

  • Making it illegal to require employees to sign a waiver agreeing not to disclose compensation information.

  • Closing loopholes in how employers can justify gender pay disparities.

  • Increasing relief for employees who bring claims.

  • Requiring companies with public contracts to report compensation broken down by gender and race

The picture in Pennsylvania is much different. The state’s Equal Pay Law passed in 1959 was updated just once since then. In 1968, it was amended to cover fewer workers.

Terry Fromson, managing attorney at the Philadelphia-based Women’s Law Project, said although the law prohibits paying employees differently on the basis of sex, it allows them to set pay based on such things as pay history and seniority, which she argues are greatly influenced by sex.

Last week, Rep. Brian Sims (D., Phila.) reintroduced a bill that would require employers to count time off for maternity leave toward seniority. It would also ban retaliating against the sharing of pay information, broaden the definition of “employee,” and strengthen protections for workers who bring claims. It would also add fringe benefits to the law, which currently only prohibits discrimination as it relates to wages.

Sims said he’s hopeful Republican leadership, especially those who plan to run for statewide office and see that equal pay legislation typically polls well, will get on board.

Other ways governments can address the wage gap

Here are four regulatory changes touted by women’s advocates:

  • Requiring widespread salary disclosure by companies: Dena Mottola Jaborska, associate director of New Jersey Citizen Action, said she’d like to see legislation requiring private companies to publicly disclose pay by gender and race.

  • Accommodations for pregnant women: Fromson said mandated accommodations for pregnant and caregiving women will keep them on the job longer, influencing wages over time.

  • Hiking the minimum wage: More than 60 percent of minimum wage workers in Pennsylvania and New Jersey are women, according to the National Women’s Law Center. The minimum wage in Pennsylvania is $7.25 an hour, the lowest allowed under federal law, though Republican leaders have signaled they’re open to a hike. New Jersey’s is $8.85 an hour, which will increase to $15 an hour by 2024.

  • New protections for industries dominated by female workers: Mottola Jaborska said higher pay for teachers, who are in a field dominated by women, could cut the wage gap. In addition, Philadelphia is considering legislation that would increase protections for domestic workers, an industry comprising mostly female workers.