For years, the driving organizational push of Teach For America has been to figure out how to select individuals into its program who have what it takes to move at-risk students ahead not one, but two or three grade levels in a single year. The January issue of The Atlantic takes an interesting look at that process, examining TFA's relentless pursuit to be the first to answer that question.

While TFA acknowledges the inherent imprecision involved in predicting good teachers, it sees the question settled on two points. Individuals who have a history of both perseverance and previous success are more likely to be successful teachers. Previous success is manifested in high GPAs and leadership roles. Whereas most studies over the years have not found high GPA to be a predictor of an effective teacher, within TFA's realm of candidates, it matters quite a bit. Perhaps that is because TFA teachers all come from highly selective institutions and none come from education schools, notorious for their easy A's. Other qualities that many school districts interpret as a signal of a strong candidate, such as prior experience working with children, don't matter a whit.

A new study from the Journal of Positive Psychology looking at 390 TFA teachers confirms what TFA has learned internally about key personality traits. That study measured grit (perseverance and passion for long-term goals), optimistic explanatory style (how positively a person reacts in the face of adversity) and life satisfaction (contentment with one's current life situation) . Grit and life satisfaction made the most difference in student learning outcomes.