"We have to have unions that are flexible. That are saying, we want to fight for keeping the best teachers, too."
Guggenheim's film examines the state of public education in America - by following 5 students, desperate to transfer to better schools.
"I think a lot of people think the schools are not working over there, but they're fine for me. You know-- kids are-- kids are dropping out but not me. And that's what this movie is, it's a wakeup call, saying they aren't working for every kid," Guggenheim said.
Three educators joined the conversation via Skype. Harlem principal Barbara Freeman thought the film was "a little slanted."
"I think that there are a lot of great public schools with great teachers, and great administrators, and great families that I would have liked to have seen," Freeman said. "I didn't feel it was a true portrayal of what is happening in all schools."
The film opens in select theaters, Friday.