When federal statistics showed test scores lower in charter than in regular schools, some charter school supporters insisted this must result from charter schools enrolling harder-to-teach minority students. Data show, however, that typical charter school students are not more disadvantaged, yet their average achievement is not higher. Even if some charter schools are superior, deregulation also permits charter schools that are inferior, with average performance no higher than in regular public schools. Debates spurred by federal charter school test data show how all debates about education could be improved: by carefully accounting for the difficulty of educating particular groups of students before interpreting test scores, and by focusing on student gains, not their level of achievement at any particular time.