Here’s Duncan’s full answer (emphasis mine):

Well, let me just say, in Chicago, and I’m sure this is true nationally, we had great union schools and we had poor union schools, and we had great non-union schools and we had poor non-union schools. And so, that’s a piece of the puzzle, but it’s much more complex than that.

Does a third-grader know whether they’re going to a union school or a non-union school? They don’t know that. And frankly, they don’t care. All they care about is, are they being challenged. What I want to do, Tom, I want to be very, very clear: I want to take to scale what is working and I want to eliminate what is not working. There are great examples of success in those two camps and there are examples of failure.

Duncan also demonstrated even-handedness in talking about the current contract debate between Michelle Rhee, the D.C. schools chancellor, and the teachers union there, which, like New York City’s union, is part of the national American Federation of Teachers. “I have a lot of confidence in the chancellor, Michelle Rhee, and Randi Weingarten, the president of the AFT, doing the right thing by children,” Duncan said.

The equal time for Rhee and Weingarten comes after Obama heaped praise on Rhee alone during the campaign. It also offers evidence for exactly how Duncan plans to approach debates inside the Democratic Party on education. The model here is to cite pragmatism above ideology: He doesn’t voice any faith in the labor movement as a cause, or, alternatively, voice disapproval of it. He simply says he wants to support “what works.”

You can listen to Duncan’s full interview, which included the fun fact that Duncan’s family did not have a television set when he was growing up, here.