Barack Obama ad says women are paid "77 cents on the dollar for doing the same work as men"

Article here. Excerpt:

'The 77 cent figure has become a rallying cry for those who seek to eliminate employment discrimination based on gender. And it’s a genuine statistic. In a report released in September 2011, the U.S. Census Bureau wrote that in 2010, the female-to-male earnings ratio of full-time, year-round workers was 0.77." Translated into dollars, that means that in 2010, women working full-time earned 77 cents for every dollar earned by men working full time.

But the Obama ad takes a solid statistic and describes it incorrectly. The campaign is wrong to say that the 77-cent figure describes the pay differences between men and women "doing the same work." (By contrast, former Virginia Gov. Tim Kaine recently earned a Mostly True on a similar claim because he was not specifying the number was for the same occupations.)

The 77-cent figure compares all male and female workers, regardless of their occupation. Whether due to a historical legacy of discrimination or because of personal choice, women and men are disproportionately represented in certain jobs. For instance, women dominate the ranks of receptionists, nurses, and elementary and middle-school teachers, among other fields. Men are disproportionately truck drivers, managers and computer software engineers.'