President Barack Obama commemorated Equal Pay Day this week by saying that women are paid less than men, only to undercut his argument with a lousy comparison. The larger problem isn't that women are paid less than men for the same work; it's that the American workplace puts women at a disadvantage before any apples-to-apples comparison can be made.
Accounting for differences in the types of work men and women do, experience, education and hours, the pay gap shrinks from Obama's 23 percent to 12 percent. But that reduction shouldn't be interpreted as a victory against sexism - it should be seen as proof that the problem is in many of those factors that explain women's disadvantage.
Take occupations. One of the more disturbing signs is that industries where women had made limited progress in the 1970s and 1980s but never fully broke through - such as manufacturing and information - are slipping back toward male-only domains.
Women made up 32 percent of manufacturing workers in 1990; as of last month, that figure had fallen to 27 percent, lower than in any year since 1971. In the information sector, which includes computer engineering, telecommunications and traditional publishing, women's share of jobs has dropped to the lowest on record: 40 percent, down from 49 percent in 1990.
The social concept of a "man's job" or a "woman's job," that is, has sharply reasserted itself over the last two decades. Industrial change - such as technology replacing workers in manufacturing - is pushing out women more so than men.
Those reversals are a serious concern. Economists explain away about a third of the pay gap according to workers' choices of occupation and industry. Implicit in their framework, though, is the idea that men and women fully choose their career. A retrenchment of the "man's job" world weighs against the view that much progress has been made.
Or take hours. The last great obstacle to women's advancement is that employers in certain industries are inflexible about accommodating the needs of employees to work certain schedules, said Claudia Goldin, past president of the American Economic Association, in a paper last year.
This makes it harder for mothers and married women - and helps limit some fields to men, who don't face same social expectations. The least flexible occupations, she also found, were the ones with the worst gender pay gaps.
Differences in occupations and working hours aren't things to use to explain away the gender gap. They're parts of it.
Conservatives aren't just a bit too ready to brush off evidence of a gender pay gap. They've chosen to ignore lingering inequity. They seem to fear that any talk of a pay gap will build support for changing the legal standards for lawsuits against pay discrimination.
When Obama talks about the pay gap, he often mentions his support for a bill that would ban employers from retaliating against employees who discuss wages and would flip an important legal burden of proof. Instead of workers having to prove that differences in their pay are sexist by design, employers would have to show that gender pay differences are driven by education, training, experience or a similar factor - and that they are incapable of designing a pay system without gender differences.
It's reasonable to think that this standard is too high - that, in seeking to punish discriminatory employers, it exposes too many well-behaved ones to lawsuits. Conservatives don't have to support that proposal. They do, though, need to figure out an agenda to advance women in the workplace.
Evan Soltas is a contributor to Bloomberg View.