In Waiting For "Superman", Davis uncovers a secret code some principals use to deal with bad teachers, called "the dance of the lemons."

In this shocking scenario, principals simply trade off their bad teachers—their lemons—to principals at other schools, hoping that the lemon they receive isn't as bad as the lemon they got rid of.

"Why can't you just fire bad teachers?" Oprah asks.

"It's actually incredibly difficult to fire an ineffective teacher. You have to basically meet a criminal standard," Michelle says. In one case, Michelle says a teacher in her district would disappear from the classroom, skip work day after day and fall asleep in class, but when the district tried to terminate her, she only earned a 10-day suspension.

"Finally, last year we were able to terminate this person, but it was after [she] had been in the classroom for 10 years," Michelle says.