Charter schools are controversial, but a new analysis of Boston’s charter high schools has found that they have had persistent positive results. Students attending these schools—which use lotteries for admission—were more likely to pass the state graduation exam and qualify for a state-sponsored college scholarship, got higher SAT scores, sat for more AP exams, and were more likely to attend four-year public colleges in Massachusetts. These gains were larger for boys, special education students, and students with initially low achievement.