Probably extrapolating from anecdotal evidence (possibly including personal experience). Also, some studies have shown systemic underpayment of minorities.

https://www.bloomberg.com/news/articles/2018-12-27/u-k-s-und...

https://www.nydailynews.com/new-york/eeoc-nyc-owes-underpaid...

https://www.pinnaclepeople.com.au/news/underpayment-of-hospi...