I'm headed to some teacher professional development at school this morning. We'll spend our time talking about ways to improve our school.

But this remarkable article from Stanford professor of education and sociology Sean F. Reardon notes that, despite all of the improvements our public schools have made over the last few decades (and don't be fooled: we are improving, not failing), the gap between rich students and their poor and middle-class counterparts has grown. Income now explains more of the achievement gap than race. What's happening? Parents are just being good parents... but thanks to growing inequality, rich parents have much more to spend on helping their kids than the rest of us:

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.

With a college degree insufficient to ensure a high-income job, or even a job as a barista, parents are now investing more time and money in their children’s cognitive development from the earliest ages. It may seem self-evident that parents with more resources are able to invest more — more of both money and of what Mr. Putnam calls “‘Goodnight Moon’ time” — in their children’s development. But even though middle-class and poor families are also increasing the time and money they invest in their children, they are not doing so as quickly or as deeply as the rich [Sean F. Reardon, "No Rich Child Left Behind," New York Times, 2013.04.27].

Parents at all levels are acting in the best interests of their children. But rich parents have a growing advantage in the opportunities they can provide their kids outside of the public school resources available to all of us. That growing advantage is crowding out social mobility.

Restoring social mobility won't be easy. It will take more than my Spearfish colleagues and I will be able to come up at our two-hour meeting this morning. But Reardon points to policies like better maternity and paternity leave and support for better daycare to give all kids access to the advantages currently claimed by the lucky few riding the wave of income inequality.