Keeling conceded there "has been some skepticism about whether new, alternatively certified teachers could measure up. These results suggest that they can, if they are carefully selected and rigorously trained."
The question is not "can carefully selected and rigorously trained" "alternative" teachers be successful, but "is your training actually effective?" Given that you're probably comparing it to low-quality certification training, that's a low bar.
Also, what about this?
Over those years, schools attracted particularly large numbers of teachers considered to be at the peak of their careers - with between five and 10 years' experience. "I think it's good news . . . that retention is up, because that means less rookie hiring, and we know less rookie hiring is good for kids," said Jonah Rockoff, an associate professor at Columbia Business School.
GothamSchools morning news roundup is bad for my productivity.