Class size

Class size refers to the number of students a teacher faces during a given period of instruction. Dozens of studies on class-size reduction demonstrate its positive impact on student performance, though a smaller number of studies attempt to cast doubt on the connection between class size and student learning. Class size refers to the number of students a teacher faces during a given period of instruction. Dozens of studies on class-size reduction demonstrate its positive impact on student performance, though a smaller number of studies attempt to cast doubt on the connection between class size and student learning. Some researchers and policymakers have studied the effects of class size by using student-teacher ratio (or its related inverse, teacher-pupil ratio), but class size is not accurately captured by this metric. As Michael Boozer and Cecilia Rouse explain in “Intraschool Variation in Class Size: Patterns and Implications,” student-teacher ratio gives an imprecise view of class size because teachers may be unevenly distributed across classrooms. Some teachers have light course loads as they are assigned to spend most or all of their time coaching other teachers. These coaches would nevertheless factor into the calculation of student-teacher ratio. In other classes – say, an inclusion class with special education students – two teachers may jointly teach a class of thirty-four students. Although student-teacher ratio would describe this class’ size as seventeen, these teachers continue to face thirty-four students during instruction. In general, average class size will be larger than student-teacher ratio anytime a school assigns more than one teacher to some classrooms. In poor and urban districts, where schools enroll higher numbers of students needing specialized instruction, student-teacher ratios will therefore be especially imprecise measures of class size. Although student-teacher ratio does not measure class size, some important studies and surveys have used student-teacher ratio as a proxy for class size. Indeed, some critics of class size reduction, including Malcolm Gladwell's David and Goliath, cite a 1986 study by Eric Hanushek, “The Economics of Schooling: Production and Efficiency in Public Schools,” that relies on a literature review of data on student-teacher ratio instead of class size. See Class-size reduction for a full discussion of Hanushek’s thesis.