When you see that 76 percent of teachers are female, I think you have to acknowledge that there's a cultural bias, and it does date back to this nineteenth century idea that teaching is a form of mothering.

A lot of charter schools are non-union schools that take a lot of teachers from alternative tracks, like Teach For America. They do this in part because a lot of charter schools have very strong ideologies around how they want teachers to teach. And they find that starting with a younger or more inexperienced teacher allows them to more effectively inculcate those ideas.

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.

I don't think school reform should be motivated by missionary zeal. I think it should be motivated by evidence of what works.

The first generation of school reformers I talk about - nineteenth century education reformer Horace Mann, Catharine Beecher - they are true believers in their vision for public education. They have a missionary zeal. And this to me connects them a lot to folks today, whether it's education activist Campbell Brown or former D.C. public schools chancellor Michelle Rhee. It's a righteous sense, a reform push that's driven by a strong belief in a particular set of solutions.

What happens from about 1954 to the late 1980s, is that we see a huge wave of optimism that school desegregation is going to be the way to improve educational outcomes for poor children of color. And we see a consensus build on the left and in the center that this is going to be a transformative education movement like none other we've seen in American history.

I always make the point that teachers are people too, and that they don't just want to be in front of kids all day and have children be their only feedback loop.