Finally everyone is admitting what high-end private schools have been saying for years: The most important indicator of future success in kids is grit. Even the Obama administration has joined the grit bandwagon. Educators define this as the ability to keep trying hard in the face of very bad odds.

It's not controversial that kids need to learn grit. It is controversial that it could even be taught in school. Angela Duckworth, an psychology professor at University of Pennsylvania, developed measures for kids to assess their own grit. She points out that it's difficult for schools to measure grit, which makes it difficult to include it in school curriculum.

New York City public schools have resorted to teaching kids grit by having them read about people who did great things after a failure. But it seems to me that this isn't teaching grit, it's teaching history.

Grit takes years to develop. You need to be dedicated to something, and then you need a setback to overcome.

The precondition for grit is passion. We find grit by putting our heart and soul into something we love. In a classroom, kids choose from the opportunities a teacher provides. Obviously, this is very limited, and it's hard to believe that all kids will find their passion within the confines of a classroom.

You know how you can tell if you are teaching your kid grit? If you want to protect him from over investing in a path to disappointment. All the times people have said to me: "What do you expect your son to be? A professional cellist? That's not very likely."

I answer that question once a week. Often in front of my son. As if he can't hear. That's how I know what grit is. He's completely over-invested in playing cello. I get it. But grit is over-investment. And school can't provide that. So we pretend to not value it, and we question parents who allow it. Instead of encouraging kids who are exhibiting grit we admonish them as outliers with unreasonable dreams.