This document discusses applying lessons from evidence-based medicine to leadership development. It proposes moving leadership development to a more "evidence-based" approach where the effectiveness of programs is measured by their impact on business results, not just participant satisfaction or learning. The document outlines a four-step process for organizations to directly link leadership development activities to key business strategies and measurable outcomes. Case studies are provided that measure the impact of leadership behaviors on employee commitment and link development programs to improving those high-impact behaviors.