The wage gap the National Women’s Law Center reports at the national and state levels are the same ones reported by the Census Bureau – the median earnings of women full-time, year-round workers as a percentage of the median earnings of men full-time, year-round workers. Median earnings are the earnings made by an individual at the 50th percentile – the worker right in the middle. Earnings include wages, salary, net self-employment income but not property income, government cash transfers or other cash income – so basically what people get paid for working. Working full time means working at least 35 hours a week and working year round means working at least 50 weeks during the last twelve months (This includes sick leave and paid vacation. School personnel are also included if they are returning to work in the fall).

The national wage gap data comes from the Current Population Survey and state wage gap data comes from the American Community Survey. For the state level wage gap workers 16 and older are included. At the national level, 15-year-old workers are also included. The wage gap is not broken down by occupation or industry, though data on earnings by industry and occupation for women and men are available from the Bureau of Labor Statistics.