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Chalk this up to another instance where a girl just can't win.

You know that stubborn pay gap between the sexes? (In big firms, women earn 90 to 94 percent of what men earn in the same position, according to the National Association of Women Lawyers.) Well, the gap might be so entrenched that measures aimed at eradicating it aren't helping, and, in some cases, make it worse.

That's the cheerful finding described in an article in Harvard Business Review by Lydia Frank, a vice president for PayScale, a compensation data company. Based on responses from more than 15,000 job applicants, Frank looked at the effect of the ban on asking job seekers about their salary history. (New York City, Oregon and Massachusetts have adopted the ban, and over 20 states are considering it.)

The ban is meant to foster pay equality, but the result was the opposite. Writes Frank in HBR:

The widely held assumption is that revealing your salary history, especially if the number is below market value, could negatively influence the offer made by the employer with whom you're interviewing. However, this study revealed that a woman who was asked about her salary history and refused to disclose was actually offered 1.8 percent less than a woman who was asked and did disclose. Meanwhile, if a man refused to disclose when asked about salary history, he received an offer that was 1.2 percent higher than a man who did.

How screwy is that? Men get a bump but women are penalized for doing the same thing. Frank offers two explanations for this result: one, employers don't like women who push for more money; and two, employers might assume that a woman who refuses to disclose her salary is earning less than she's paid.

To the above, I'd add a third reason: We expect a woman to be more honest, and by refusing to reveal her salary, she's more apt to be perceived as cagey. (Need I remind everyone that Hillary Clinton kept getting slapped with the “untrustworthy” label during the campaign, while Trump's questionable dealings and refusal to disclose his taxes were considered marks of business savvy?)

So how does all this play out in the law arena—say, when a lawyer is making a lateral move? On one hand, “the market rate for lawyers tends to be more transparent,” says consultant Carol Frohlinger, who often writes and speaks about negotiation techniques for women. “That's good news for women because research shows that when women are aware of the going rate, they are more likely to ask for it.”

While the compensation for lateral associates might be set, what about lateral partners? Is it possible that firms will offer female partners less money because of hidden biases?

“My guess is yes,” Frohlinger says. “The size of the potential book of business is key to what partners can command when they move. Men may be more 'optimistic' than women who are often concerned about over-promising and under-delivering.” And she adds, “whether or not they can actually get the business to follow is a whole different conversation.”

Women laterals are sometimes offered less money than men, says recruiter Natasha Innocenti, “because I find women more prone to keeping their groups together, which can sometimes cannibalize their compensation in cases where women lead the group.”

In addition to hidden biases, women might not be blowing their horn as loudly or be as money-conscious as men. So is the solution for women to do more self-promotion and be greedier?

Maybe, but Frohlinger cautions that women might be getting too much advice. “There's a lot of conflicting and confusing and some bad advice out there for women regarding compensation negotiations,” she says. “In my experience, success hinges on being able to assess the situation and prepare well rather than defaulting to 'rules.'”

She's right. Women are getting saturated with studies and advice, and no one knows for sure what's working.

Which means women will chug along. And that gender pay gap is likely to stay.