What is news is that in the United States over the last few decades these differences in educational success between high- and lower-income students … - Sean Reardon

We’ve barely given a thought to what the rich were doing. With the exception of our continuing discussion about whether the rising costs of higher education are pricing the middle class out of college, we don’t have much practice talking about what economists call “upper-tail inequality” in education, much less success at reducing it. Meanwhile, not only are the children of the rich doing better in school than even the children of the middle class, but the changing economy means that school success is increasingly necessary to future economic success, a worrisome mutual reinforcement of trends that is making our society more socially and economically immobile.

But rising income inequality explains, at best, half of the increase in the rich-poor academic achievement gap. It’s not just that the rich have more money than they used to, it’s that they are using it differently. This is where things get really interesting. 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. They are doing this because educational success is much more important than it used to be, even for the rich.

If not the usual suspects, what’s going on? It boils down to this: The academic gap is widening because rich 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. As you may have heard, the incomes of the rich have grown faster over the last 30 years than the incomes of the middle class and the poor. Money helps families provide cognitively stimulating experiences for their young children because it provides more stable home environments, more time for parents to read to their children, access to higher-quality child care and preschool and — in places like New York City, where 4-year-old children take tests to determine entry into gifted and talented programs — access to preschool test preparation tutors or the time to serve as tutors themselves.