Why Don't the Best Nonprofits Grow?

Why don't the best social-purpose organizations grow? First off, let me acknowledge that growing any type of organization — for-profit or mission-driven — is tough to do. My work at the Social Innovation Fund and prior experience in venture philanthropy investing, foundation grant making, and strategic consulting taught me that. However, my experience also showed me that there's a critical issue holding back those who want to do good: Lack of evidence.