Roland Fryer is a brilliant economist  - among the youngest scholars to ever earn tenure at Harvard - who studies schools. And education, he realized, has its own coconut-cake problem. There are public schools that are performing near miracles in deeply troubled urban districts, but nobody, not even those who run these schools, can say for sure what makes them work. Everyone has their theory - a longer school day, a little more discipline - but nobody knows the actual recipe. So Fryer went to New York City and measured the ingredients. working with Harvard’s Will Dobbie and a team at the Harvard EdLabs, Fryer collected an unprecedented amount of information from a diverse group of 35 charter schools - everything from test scores and spending per pupil to educational philosophies and videotapes of classroom instruction. Then, using rigorous statistical techniques, he compared differences in student achievement with all the other variables, extracting five principles that the star charters all share.