Writing for the new edition of The Atlantic, Amanda Ripley talks to the Teach for America (TFA) crew about what they’ve learned about quality teaching from their vast stores of data. We know quality instruction can make a huge difference, but you may be surprised to learn what characteristics TFA finds match up with making the biggest positive impact on student learning:

What did predict success, interestingly, was a history of perseverance—not just an attitude, but a track record. In the interview process, Teach for America now asks applicants to talk about overcoming challenges in their lives—and ranks their perseverance based on their answers….

But another trait seemed to matter even more. Teachers who scored high in “life satisfaction”—reporting that they were very content with their lives—were 43 percent more likely to perform well in the classroom than their less satisfied colleagues. These teachers “may be more adept at engaging their pupils, and their zest and enthusiasm may spread to their students,” the study suggested.

In general, though, Teach for America’s staffers have discovered that past performance—especially the kind you can measure—is the best predictor of future performance. Recruits who have achieved big, measurable goals in college tend to do so as teachers. And the two best metrics of previous success tend to be grade-point average and “leadership achievement”—a record of running something and showing tangible results. If you not only led a tutoring program but doubled its size, that’s promising.

Knowledge matters, but not in every case. In studies of high-school math teachers, majoring in the subject seems to predict better results in the classroom. And more generally, people who attended a selective college are more likely to excel as teachers (although graduating from an Ivy League school does not unto itself predict significant gains in a Teach for America classroom). Meanwhile, a master’s degree in education seems to have no impact on classroom effectiveness.

When hiring across the board for teachers, especially to serve student populations that are the neediest, are these traits what our schools are screening for? Or are less meaningful credentials simply checked off a list?

Presuming TFA’s findings are accurate — and there’s no reason to doubt them — the real challenge is how to scale up outstanding teaching to make the biggest impact on the most students’ lives possible. But at least the course for getting there has been charted more clearly.

If you only read one new article about education this week (outside of my blog and the great work of my friends at the Education Policy Center), make the Atlantic piece on good teaching the one.