WHEN Roland Fryer was a teenager, he hung out with a bad crowd. Surrounded by drug dealers and getting into fights, he used to sell counterfeit handbags to make a bit of extra cash. Asked by a friend where he would be at 30, he replied that he would probably be dead. In fact, at that age, in 2008, he became the youngest African-American to win tenure as an economics professor at Harvard. On April 24th the American Economic Association (AEA) announced that he had won this year’s John Bates Clark medal—the profession’s second-highest honour after the Nobel prize. He is its first black winner.

The Clark medal—awarded to the most promising American economist under 40—was given for Mr Fryer’s work on improving “our understanding of the sources, magnitude, and persistence of US racial inequality”. His research has sought to explain why black children do so much worse in life than their white peers—and why relatively few have, like him, overcome their rough backgrounds.

One of his early studies asked why black kids do worse than whites at school. He found that, after controlling for such things as income, there was no gap in kindergarten. But over time, black pupils lost ground in virtually every subject. By the middle of third grade (at around nine), they were 20% less likely than whites to be able to perform tasks such as multiplication.

One explanation, long dismissed as an urban myth, was that black pupils do not study hard because those who do are accused by their peers of “acting white”—and ostracised. Mr Fryer found a novel way to test this notion. He measured how popular pupils were by asking them to name their friends. To guard against fibbing, he counted a friendship as real only if both children named each other. He found that the myth was true. Black high-school students with good grades had fewer friends than those with mediocre ones. For whites, the reverse was true.

How, then, to persuade slackers to study harder? Mr Fryer suggested offering small cash rewards to children who meet certain goals, such as memorising their times tables. This was surprisingly effective. One of his experiments in Houston’s elementary schools showed that, for every 10% increase in incentive payments, pupils worked 8.7% harder. (By comparison, a similar increase in wages spurs adult males to work only 3.2% harder.)

Mr Fryer’s next challenge is to study racial inequality outside the classroom. He plans to test whether there is a racial bias in police shootings. This is much harder than it sounds. It is not enough to show that cops are more likely to shoot black citizens than white ones (which they are). You have to show that they are more likely to shoot blacks than whites under the same circumstances. It should be possible to use police data to control for things that might prompt a cop to open fire, such as whether a suspect was holding a gun when being arrested. The results, Mr Fryer says, may help the police figure out how to reduce the death toll. With Baltimore in flames and Ferguson still reeling from riots over police heavy-handedness, such dispassionate research is urgently needed.