The world is beset with enormous problems. And as a nonprofit, NGO, foundation, impact investor, or socially responsible company, your organization is on a mission to solve them. But what exactly should you do? And how will you know whether it's working? Too many people assume that good intentions will result in meaningful actions and leave it at that. But thanks to Marc Epstein and Kristi Yuthas, social impact can now be evaluated with the same kind...