Here are two things Americans love: inventiveness and upward mobility.The idea that becoming an inventor can offer a way to climb the income ladder is therefore an intoxicating one. More entrepreneurialism and more equality: who could be against that?

There are however some challenges here. First, entrepreneurs are, by definition, risk takers. When their risks pay off, they become rich and likely famous. But when they do not, they face financial ruin, unless they have a financial cushion.

Second, most of America’s inventors come from affluent families, at least on some measures. The odds of becoming a patent holder are very much higher for those from rich families, as Alex Bell, Raj Chetty, Xavier Jaravel, Neviana Petkova and John Van Reenen show in their just released paper "Who Becomes an Inventor in America? The Importance of Exposure to Innovation." The rate of patenting among those who grew up in top quintile households is more than double the rate of those who grew up in households in the middle 40 percent of the distribution.

Read the full article about class gaps in patenting by Richard V. Reeves and Nathan Joo at Brookings.