In discussing EVALUATION AND IMPACT, it is easy to get caught up in a numbers game. There is tremendous pressure to report on how our work is making a difference, and scale ("Billions and billions served!") seems like the most expedient way to demonstrate why our organizations and our programs matter. When the goal is simple volume – for example, how many people can we move through this drive-in window? – the metrics can indeed be straightforward. But if the goal is changing social behaviors – how can we get students to stay in school, or how can we break the cycle of poverty, or how can we improve health outcomes? – the numbers can tell us a great deal, but rarely can they tell a complete story.