Lean in .  Opt out .  Negotiate up .

These days, there’s no shortage of advice for women about how to get promoted, manage their careers and personal lives, and receive equal pay. But what if women don’t think they need it?

A new  Gallup poll of 1,039 women during early August found that 15 percent of U.S. working women say they have at some point felt passed over for a promotion or opportunity at work because of their gender. Meanwhile, 13 percent feel gender has played a role in their being denied a raise at work. The results were roughly similar when accounting for age, education and type of employment.

While 15 percent–or even 13 percent–is higher than anyone would want it to be, it’s interesting to me, given all the attention to the subject, that the number isn’t higher. One explanation, of course, is that discrimination in the workforce is really improving. And to some extent, it is. But perceptions are also hard to get right: Studies  show that men are still promoted at higher rates than women. One researcher after another has revealed that men are favored for jobs even when male and female candidates are equally –or even  identically –qualified. Meanwhile, other  research finds that men continue to get bigger raises than women, even when  women ask for them.

Heidi Hartmann, president of the research nonprofit  Institute for Women’s Policy Research , says one possible explanation for Gallup’s finding is that more women don’t think they’re subject to gender discrimination because as many as half of all employees work in “sex-segregated” jobs, or occupations that are predominantly (75 percent or more) male or female. A nurse isn’t comparing herself to an engineer, in other words–she’s comparing herself to other nurses, many of whom are female. “You’re not likely to perceive discrimination when you’re not in an environment where you’re surrounded by people of the opposite sex getting promoted and you’re not,” Hartmann says.

Another possibility, I’d guess, is that even if women believe that unequal pay, in general, is a problem for women at work, we’re not as quick to believe it actually affects us. Just as employees are notorious for thinking their  own performance is better than it often is, it wouldn’t surprise me if we’re also less likely to believe we’re subject to the same discrimination that affects others–or to know that it has actually happened to us.

Of course, that might depend on whether our political leanings are conservative or liberal. In possibly the most interesting findings from Gallup’s poll, only 10 percent of conservative women said they had ever felt denied a raise at work, while 17 percent of liberal women said they had. The magnitude of that difference is “a surprise,” Hartmann says. “But it also reflects the way the political parties position themselves.”

Jena McGregor is a columnist for On Leadership.