Everyone knows that having women on a company’s board of directors is good for the company’s bottom line. Research shows that a critical mass of THREE women results in better corporate governance. Less likely to feel like an outsider, a woman is more likely to speak up and be heard when she is one of three. Good decisions and good results follow from a balance of feminine and masculine strengths. Knowing this, leaders should not be satisfied with one (token) woman. Yet a new study shows that, at the executive level, most companies have just one woman. They have “checked the box.” With only one woman, they may miss out on the value of true gender diversity.