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What is the affect of class-size reduction in a controlled study?

Why is this question important? Why is this question important? Class-size reduction has been one of the most thoroughly studied educational interventions to be taken to scale. The STAR Project, a randomized controlled study, was conducted in the 1980's within the state of Tennessee. The STAR Project and follow-up research, such as the Wisconsin Sage Project, greatly added to our knowledge base of the effects on student performance of reducing the number of students in a classroom. Relying upon this research, California decided to make class-size reduction the centerpiece of its education reform efforts and implemented the initiative across the entire state. This sequence of events makes class-size reduction a cautionary tale and provides an excellent example of how to navigate the challenges confronted when taking new practices from research to practice.

See further discussion below.

Source:  The State of Tennessee's Student/Teacher Achievement Ratio (STAR) Project: K-3 Class-Size Study

Results: The STAR Project established that class-size reduction could be employed to improve student performance. In particular, small class sizes can produce increases in student achievement that are lasting. This was especially true for minority and low SES students. The greatest gains were for children in the early grades. In each of the grades, Kindergarten through 3rd grade students achieved higher scores in reading and math than students in larger class-sizes. The effects after 1st grade declined slightly, but remained significant through the end of 3rd grade. The study also established that a classroom teacher was the critical person in the equation. Classrooms that relied on classroom aides to achieve the desired ratio did not experience the improvement in student achievement that came with a classroom teacher.

Implications: Implications that can be derived from the study are: 1. Students can make improvement in math and reading from placement in class sizes of 13-17 students. The optimal class size was not established by this study. 2. These results were most notable for SES and racial populations that participated in the study. 3. These results can be achieved when credentialed personnel teach classrooms. Comparable results cannot be achieved by substituting para-professional for teachers as a less expensive alternative to boost ratios and save money. 4. Although it can be effective, class-size reduction is expensive and should be weighed against available alternative interventions that can improve student performance for less money.

Taking Class-Size Reduction to Scale in California : California's implementation of class-size reduction did not match that of the experience of Tennessee. In California, the student achievement gains were minimal, improvement for low socio-economic students did not occur as anticipated, and the costs of implementation had a major impact on the state's education budget.

Authors:  Elizabeth Word, John Johnston, Helen Bain, B. Fulton, Jayne Zaharias, Charles Achilles, Martha Lintz, John Folger, and Carolyn Breda

Publisher: Tennessee State Department of Education, 1990

Study Description: The study was a large scale randomized controlled trial designed to assess the effects of class size reduction on student achievement. There were approximately 11,600 students, 1,300 teachers, 76 schools, and 42 districts participating in the experiment. The study was structured to determine if students in classes consisting of 13-17 students would perform better than students in class sizes of 22-26 students. The students were achievement was assessed based upon standardized tests (Stanford Achievement Tests or SAT) as well as the state's basic skills test of reading and math. The study was completed after following the students for four years.

Definitions: 1. Class-size: The ratio of classroom teacher to the total number of students in a specific classroom. 2. Regular classroom: Classroom with a teacher to student ratio of 1 teacher to 22-26 students. 3. SES: Socio-economic status.

Citation:
Word, E. R., Johnston, J., Bain, H. P., Fulton, B. D. et al. (1990). The State of Tennessee’s student/teacher achievement ratio (STAR) Project, Technical Report 1985—90. Nashville TN: Tennessee State University.

Related Research: Class Size Reduction in California: Early Evaluation Findings, 1996-1998, Technical Report, June 1999, pg. xix, Fig. 7. http://www.classize.org/techreport/index.htm