The gender pay gap (or the gender wage gap) is a metric that tells us the difference in pay (or wages, or income) between women and men. It’s a measure of inequality and captures a concept that is broader than the concept of equal pay for equal work.
Differences in pay between men and women capture differences along many possible dimensions, including worker education, experience and occupation. When the gender pay gap is calculated by comparing all male workers to all female workers – irrespective of differences along these additional dimensions – the result is the ‘raw’ or ‘unadjusted’ pay gap. On the contrary, when the gap is calculated after accounting for underlying differences in education, experience, etc., then the result is the ‘adjusted’ pay gap.