Top executives understand that gender diversity is both an ethical and a business imperative. Yet progress is slow. Despite modest improvements, women are underrepresented at every level of today’s corporations, especially in senior positions.

When employees don’t see progress, they question their organization’s commitment to equality. For me it got personal a couple of years ago when internal research revealed skepticism at McKinsey & Co. Despite what I felt had been my clear and strong commitment to this goal, a majority...