The Chicago Mastery Learning Reading (CMLR) program provides a model of instruction and a set of instructional materials for teachers and students, from kindergarten through eighth grade, in Chicago Public Schools. An analysis of CMLR progress records for more than 240,000 students in June 1983, found that compared to 1982 and earlier years, (1) more students were working on CMLR materials at their organizational grade or above; (2) more students in each grade had mastered the CMLR material for their organizational level or above; and (3) as a result of more students working on CMLR objectives appropriate for their grade level, the percentage of students mastering a year's worth of material declined slightly. (Author/KH)