The median earnings of information technology managers (mostly men) are 27 percent higher than human resources managers (mostly women), according to Bureau of Labor Statistics data. At the other end of the wage spectrum, janitors (usually men) earn 22 percent more than maids and housecleaners (usually women). And there was substantial evidence that employers placed a lower value on work done by women. “It’s not that women are always picking lesser things in terms of skill and importance,” Ms. England said. The job of ticket agent also went from mainly male to female during this period, and wages dropped 43 percentage points.