More evidence of America's hardening class lines, per Sean Reardon of Stanford University:
Before 1980, affluent students had little advantage over middle-class students in academic performance; most of the socioeconomic disparity in academics was between the middle class and the poor.
But the rich now outperform the middle class by as much as the middle class outperform the poor. Just as the incomes of the affluent have grown much more rapidly than those of the middle class over the last few decades, so, too, have most of the gains in educational success accrued to the children of the rich. ...
[R]ich students are increasingly entering kindergarten much better prepared to succeed in school than middle-class students. This difference in preparation persists through elementary and high school. …
It’s not just that the rich have more money than they used to, it’s that they are using it differently. …
High-income families are increasingly focusing their resources — their money, time and knowledge of what it takes to be successful in school — on their children’s cognitive development and educational success.