For Ross Roberts, it was a lack of resources that drove him from the classroom. For Danielle Painton, it was too much emphasis on testing. For Sergio Gonzalez, it was a nasty political environment.
Welcome to the U.S. teaching force, where the "I'm outta here" rate is an estimated 8 percent a year — twice that of high-performing countries like Finland or Singapore. And that 8 percent is a lot higher than other professions.