The history of value-added methods in Britain dates back at least to 1982. That is when a handful of secondary schools in northeast England agreed to share data, on a confidential basis, about how much progress they were making in getting students to pass the A-level examinations required to enter universities. At least three methods of value-added analysis are now used in England. The simplest, and the one now employed by the national government, measures the progress of individual students based solely on their prior attainment. Other measures control for prior attainment in addition to a range of school-level factors that might affect students' progress, but are outside a school's control. The most complicated methods--often known as multilevel modeling--take into account both school-level characteristics and those of individual classrooms and pupils that may also impinge on academic growth.