"I don't think school reform should be motivated by missionary zeal. I think it should be motivated by evidence of what works. I have been critical of Teach For America in the past but I think one of the things about their model that's interesting is that they're constantly looking at it and whether what they're doing works and reassessing their model, and making changes. So to the extent that I believe everyone in the education sector should be looking at evidence, reassessing, making tweaks to figure out what works, I think it's a positive model."