For many parents, educators, and policy-makers in the United States, charter schools – innovative public schools that are free from much bureaucratic oversight but must “compete” for students in order to retain their charters – have held out enormous promise as a public alternative to failing traditional schools. So when the American Federation of Teachers (AFT), the nation’s second-largest teachers’ union, published a study in August 2004 that found students at charter schools performing worse than their peers at traditional public schools, more than a few hopes were dashed. But to Harvard Professor of Economics Caroline Hoxby, something in the much-publicized study seemed amiss. Hoxby quickly gathered data, and just a month after the AFT study grabbed headlines, hers – “A Straightforward Comparison of Charter Schools and Regular Public Schools in the United States” – is making news with findings showing that, on average, students in charter schools are 5 percent more likely to be proficient in reading and 3 percent more likely to be proficient in math than students at the closest public schools with similar racial composition. Hoxby used standardized test results from 99 percent of the nation’s charter schools, while the AFT study that prompted hers surveyed similar results from only 3 percent of charter schools.