The wage gap discussion in the US has long struck me as being a little strange. One side says that women make 20 percent less than men. Then the other side says that, once you control for the different labor market characteristics of men and women, the gap is much smaller. Then the first side comes back and says that the fact that men and women have different labor market characteristics is itself gendered and that this gendered sorting is still a problem.

The latter point has been the sophisticated argument about the gender wage gap for some time, an argument that seems quite persuasive to me. Unequal pay for identical work is not the only way that a labor market can be sexist. A labor market that sorts men into higher-paying jobs and women into lower-paying jobs is still sexist, just in a different way.

But what’s odd about this sophisticated argument is that its advocates all seem to be using the wrong statistics. The commonly cited National Women’s Law Center (NWLC) statistic that says women make 80 percent of what men make only compares the median earnings of full-time workers. So despite making a very compelling case against controlling for labor market characteristics, advocates end up using one of those controls for their own headline statistic. Just as it ignores gendered sorting to control for job type, hours worked, and experience, it also ignores gendered sorting to control for full-time work.