This week feminists are celebrating (or more accurately, bemoaning) a fake holiday they’ve dubbed “Equal Pay Day.” It’s a fake holiday because it’s based on a bad interpretation of the wage gap statistic, the statistic that shows men earn more money than women on average.

Of course it’s true that men earn more money: The wage gap shows the current wage disparity to be 82 cents on the dollar, based on average weekly earnings. But importantly, the raw wage gap is not a measure of discrimination against women because it’s not a measure of “equal pay for equal work;” it fails to account for many factors that affect pay, including profession, experience, hours and work conditions.