An air of mystery has long surrounded student debt. We know the total number of borrowers and their combined debt — 40 million people owe $1.2 trillion — but beyond these headline numbers, the data has been frustratingly thin. Who borrows? Who defaults? Why are so many borrowers in distress? The answers have been unclear, leaving analysts and policy makers to prescribe remedies without an accurate diagnosis of the disease.

But now the picture has become significantly sharper.

Read the rest in the New York Times.