Class Size

Class size has been studied in the United States since about 1900, yet it was still in limbo by 2008. An early econometric study tied small classes to improved student outcomes. Fredrick Mosteller, Richard J. Light, and Jason A. Sachs's study discussed only two topics as sustained inquiry in education: skill grouping and class size. They sought empirical evidence about education outcomes from heterogeneous or skill-grouped classes and about the impact of class size on student learning.

The authors found a few well-designed studies on benefits of skill grouping, and results were equivocal. They then described the Student Teacher Achievement Ratio (STAR) randomized, large-scale class-size experiment (1984–1990) that demonstrates convincingly that student achievement is better supported in smaller classes in Grades K–3, and that this enhanced achievement continues [Page 166]when the students move to regular-size classes in the fourth grade and beyond.

Mosteller and colleagues' finding is mysterious juxtaposed with a Gene Glass comment in 1992 of which he asserted that of all the areas omitted from deliberation in previous encyclopedia publications, none is more unusual than that of school class size. According to Charles M. Achilles, between the 1971 edition and second, 2003 edition of the Encyclopedia of Education, any understanding of class size and its actual uses have arguably seen both the greatest and least change among the fundamentals of education. Achilles has made that claim for the past 5 years. Even with huge increases in knowledge based upon robust research about what small classes achieve, how and why gains occur, about policy and implementation strategies, the ideologies that Glass described still hinder using small classes to improve education processes and outcomes.

With full data on 11,601 of approximately 15,000 students involved, the STAR database has been used in secondary analyses to demonstrate small-class, K–3 benefits on student long-term improvements, including large social and economic benefits such as high school graduation, college admissions, improved health, decreased grade retentions, and closing achievement gaps.

STAR, in its Lasting Benefits Study (LBS), followed students in Grades 4–8 combined with the large K–3 small-class implementation in 16 of Tennessee's poorest counties (1990–1995); this study provided a base for burgeoning U.S. and international class-size studies. Small classes were court-mandated remedies in the New Jersey Supreme Court case Abbott v. Burke (1990, 1994, 1997) and in the Campaign for Fiscal Equity in New York. After noting that Title I had failed in its mission to address equity issues, Isabel Sawhill commented on education's role for opportunity in America and identified good teaching and small classes as two measures that have been shown to improve educational outcomes. Small classes should be the cornerstone of education improvement, not ubiquitous Title I–type approaches such as projects, pull-outs, and teacher assistants. International class-size interest is shown by substantial work in Australia, Canada, the Far East (especially Hong Kong, Singapore, South Korea, and China), the Netherlands, New Zealand, Sweden, and the United Kingdom.

The profound and durable effects of small class size on students' opportunity to learn and achieve in Grades K–3 are well documented. The STAR experiment and follow-up studies such as Challenge, Enduring Effects, and other initiatives such as Wisconsin's Student Achievement Guarantee in Education, consistently demonstrated positive short- and long-term small-class effects. No negative effects on student behaviors, attitudes, or achievement were found. Less is known about how small classes influence achievement in the middle grades.

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