In 1988, Margaret Thatcher, the United Kingdom’s famously conservative prime minister, approved a revolutionary reform: Allow secondary schools to shrug off local control and become autonomous, central government- funded entities. To convert into one of these so-called grant-maintained schools (GMs), a school had to secure the majority vote of its students’ parents. By 1997, some 900 of the United Kingdom’s 3,500 state-funded secondary schools had gone GM (the rough equivalent of a conversion charter school in the United States). Damon Clark’s father was the principal of a GM school. Two decades later, Clark is an assistant professor of economics at the University of Florida, where he has uncovered the first evidence that GM schools fare better than standard schools on national exams. “GMs increased the pass rate on their Grade 11 exams by about 5 percentage points,” from a 40 percent to a 45 percent pass rate, he says. He further finds that upturns emerged as early as two years after the GM conversion and persisted eight years later, at the end of his study. In both the United Kingdom and the United States, advocates of charter schools and their analogs contend that giving schools greater autonomy not only will…