Forget the affinity groups. Ditch those expensive consultants. And stop—just stop—telling me how hard your firm has been trying to fix the problem.

If you sincerely want to stem the departure of midlevel and senior female lawyers at your firm, you can start by giving women real leadership positions. By that, I mean appointing female partners to the management, executive, or compensation committee. Not those peripheral committees—like diversity, marketing, or recruiting. And I don't mean just put one or two women in positions of power either.

That's not my brilliant idea, but the finding of the New York City Bar Association's newly released study on diversity. (Yesterday, I posted an overview of the report.) The study finds that "having a critical mass of women on the management committee—defined as three or more in our analysis—was associated with higher representation of women at nearly all levels."

Let me repeat: "A critical mass of women" on the key committee resulted in more women "at all levels." Here's the nitty-gritty, according to the report:

A substantial 24 percent of signatory firms reported a minimum of three women management committee members and among these firms women represented 41.8 percent of new partner promotes, 21.9 percent of partners (20 percent equity and 28.7 percent income), and 23.8 percent of management committee members.

But for firms with no women on the management committee, the numbers for women partners were substantially lower. Those firms "reported 30 percent women new partner promotes and 15.8 percent of women partners (22.7 percent income and 15.2 percent equity partners)."

To me, the finding was stunning. The report doesn't say why having women in firm management helps level the gender gap, but I'll venture some guesses. First, I think women in leadership roles serve as crucial role models. If you can't identify with those in power, it's very hard to aspire toward it. Second, having a "critical mass" of women in power makes it much easier for women to advocate for other women and, ultimately, to change that ineffable thing called culture.

In a way, it's such an obvious fix. But it's also painfully obvious why women lag so far behind. The reality is that, at most firms, few women have meaningful leadership roles. Although there are typically nine members in the management committee, according to the study, few women occupy those seats:

In 20 percent of signatory firms there is not a single woman sitting on the management committee, in 55 percent women account for one or two management committee members, and in 24 percent of signatory firms there are at least three women represented.

The bar report says those numbers are comparable to ones that the National Association of Women Lawyers found in its study of the nation's 200 largest firms. So that means women's voices are barely heard—if at all—at about three-quarters of the firms in this country.

And you're still insisting your firm has racked its brains on how to retain female lawyers?

Give me a break.

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