The study looked at the pay gap between men and women with PhDs in the US. They found that in 2013 and 2019, women with PhDs earned 17% and 21% less than men, respectively. The wage gap was broken down into observed and unobserved factors, with unexplained differences being 5% and 12% in those years. Women earned less due to factors like less experience and being in different job categories. In the business sector, these factors accounted for over 40% of the wage gap.