Class-size reduction

As an education reform, the broad goal of class size reduction (CSR) is to increase the number of individualized student-teacher interactions intended to improve student learning. A reform long holding theoretical attraction to many constituencies, some have claimed CSR as the most studied educational reform of the last century. Until recently, interpretations of these studies have often been contentious. Some educational groups like the American Federation of Teachers and National Education Association are in favor of reducing class sizes. Others argue that class size reduction has little effect on student achievement. Many are concerned about the costs of reducing class sizes.

The two most prominent CSR studies are Project STAR, which was conducted in the mid- to late-80s in Tennessee and Project SAGE, conducted in the early 2000s in Wisconsin. Studies following the work of Project STAR and SAGE found that, even when reintroduced to larger class-sizes later in their educational career, the positive foundation for learning caused students to later in life to be more likely to take advanced classes, graduate from high school, attend college, and major in a STEM field.

Subsequent research on the effects of class size reduction has linked small class sizes with a variety of cognitive and non-cognitive benefits for students and teachers, both short and long-term, especially when class sizes are reduced in the early grades. Its benefits are particularly pronounced for lower-income students and children of color, who experience two to three times the gains from smaller classes, leading CSR to be one of only a few education reforms proven to reduce the achievement gap. Smaller classes have also been found to have a positive impact on school climate, student socio-emotional growth, safety and suspension rates, parent engagement, and teacher attrition, especially in schools with large numbers of disadvantaged children.

An early complication in measuring the efficacy of class size reduction was the tendency for different ideological camps to use different definitions of class size in the literature. As a direct measure of the number of students in each class, group size is currently understood by the educational community to be the best measure of a teacher's "true opportunity to build direct relationships with each student." A more malleable definition and one now held in dubious regard,pupil to teacher ratio, would declare a situation in which one teacher leads a class while another does paperwork in the back but does not interact with students as being half as large as its group size.

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