Why is there a wage gap for women and people of color? We just found out one cause, and how to reduce the gap.
In 2016, I was lead sponsor of Massachusetts Pay Equity law. Advocates told us that employers' requests for salary history perpetuate wage discrimination. So we included the country's first ban on requesting salary history, which has now been adopted in 18 other states.

Forbes also reported that "The study found a 5% increase in pay for all job changers, an 8% increase for women and a 13% increase for Black workers in areas that had enacted a salary history ban."
It's worth reading one author's tweet thread which started:
"Some people claim there is no systemic discrimination in the US. Our new paper ssrn.com/abstract=36287 finds that a recent policy change reveals how much institutions have been perpetuating pay inequities. 1/"
It is extremely rare to find out so clearly the effects of legislative work. I am excited to find that our efforts are raising the pay of so many people, particularly for women and Black workers, who have been under-paid and under-valued.