In the past 40 years, corporations have tackled the challenge of women's advancement by working diligently on two fronts. They have worked on the women. They help women set career goals and tell them what skills they need to enhance in order to get ahead - leadership, self-promotion, negotiation and more. They have worked on corporate practices and policies. Instituting open job posting, mentoring programs, flexible work, day care options, maternity leave options and more. And they've gotten each of these areas about 66% right. As a result, women have made great strides into middle management. But they have not made great strides into senior leadership. One reason is what I call The Missing 33%™.