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Small elementary classes

Health Factors: Education
Decision Makers: Educators State Government
Evidence Rating: Some Evidence
Population Reach: 1-9% of WI's population
Impact on Disparities: Likely to decrease disparities

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Class size reduction efforts reduce the ratio of students to educators in a classroom. Class size refers to the number of students assigned to a classroom; measures of class size do not account for the number of educators in the classroom, often called the student-teacher ratio. In K-3 elementary schools, the average difference between student-teacher ratio and classroom size in the 2013-14 school year was 9 or 10 students; an elementary school with a 16:1 school-wide student-teacher ratio had an average class size of 25 or 26 students (NEA-State rankings 2014).

Expected Beneficial Outcomes

Increased academic achievement
Increased high school graduation

Evidence of Effectiveness

There is some evidence that smaller classes modestly improve academic outcomes (Konstantopoulos 2011, Mosteller 1995, Nye 2004, Finn 2005, Cho 2012), especially when implemented in kindergarten or first grade (Ding 2010, Brookings-Chingos 2011, CPE-Class size 2005, Watson 2013). However, class size reduction efforts typically have small effect sizes, perhaps due to continued use of teaching methods applied in larger classes (Hattie 2005). Additional evidence is needed to confirm effects.

A small first grade class can modestly improve outcomes for students who were in larger kindergarten classes (Ding 2010). Overall, reductions in class size appear to benefit students who struggle in school more than high achieving students, and smaller classes appear to have smaller achievement gaps than classes with more children (Bosworth 2014). Studies of Tennessee's Student–Teacher Achievement Ratio (TN STAR) experiment indicate that small classes have the greatest benefits for children from low income households and minority students (Reynolds 2010a, CPE-Class size 2005, Mosteller 1995), and improvements in reading skills among  minority students persist for at least five years (Nye 2004). Small classes from kindergarten to second grade may improve graduation rates for low income children, especially those who are placed in a small third grade class (Finn 2005).

Smaller classes appear to have modest positive effects on academic outcomes when teachers adopt teaching practices that take advantage of smaller class environments (Watson 2013), increasing individual attention and student-teacher interactions (Blatchford 2011). Class size reduction efforts also appear more likely to affect academic outcomes when implemented with professional development efforts that support teacher and staff use of teaching techniques, classroom management, and student interaction strategies suited to small class environments (Harker 2004, CPE-Class size 2005). Class size reductions may also improve student and teacher work environments (Hattie 2005).

Class size reduction efforts frequently require additional classroom space (CPE-Class size 2005). Principals willing to fundamentally restructure school space can overcome space challenges. Principals can also deploy funding streams creatively to reduce class size (Burch 2010). Researchers suggest that many interventions can more cost effectively improve academic achievement than class size reduction efforts; tutoring and professional development are two examples (Brookings-Chingos 2011, Hattie 2005).


United States

In 2009, 23 states had enacted policies to reduce class size to a level below 20 students per classroom; 15 of those states focus on students in grades K-3 (ECS-Zinth 2009). By 2010, 35 states had laws restricting the number of students allowed in a general education classroom. Following the economic downturn, however, 19 states relaxed or eliminated these laws (Ed Week-Class size 2011). 

In 2016, Arizona introduced a bill for a class size reduction and teacher retention program in grades K-3 (NCSL-Early ed tracking 2016).


Wisconsin’s SAGE program was established in the 1996-97 school year and will be phased out at the end of the 2017-18 school year and replaced with the Achievement Gap Reduction (AGR) program. In the 2015-16 school year, 96 of Wisconsin’s SAGE schools transitioned to the AGR program. The AGR program requires participating schools to implement at least one of three strategies, including class size reductions or improved student-teacher ratios (WI DPI-SAGE). 

Implementation Resources

Burch 2010* - Burch P, Theoharis G, Rauscher E. Class size reduction in practice: Investigating the influence of the elementary school principal. Educational Policy. 2010;24(2):330-58. Accessed on December 7, 2015
WI DPI-SAGE - Wisconsin Department of Public Instruction (DPI). Student achievement guarantee in education (SAGE) program. Accessed on December 12, 2015

Citations - Description

NEA-State rankings 2014 - National Education Association (NEA). Rankings of the states 2013 and estimates of school statistics 2014: For population, school enrollment, classroom teachers, student expenditures, general financial resources, and school revenue. Accessed on March 30, 2016

Citations - Evidence

Blatchford 2011* - Blatchford P, Bassett P, Brown P. Examining the effect of class size on classroom engagement and teacher-pupil interaction: Differences in relation to pupil prior attainment and primary vs. secondary schools. 2011;21(6):715-730. Accessed on March 30, 2016
Bosworth 2014* - Bosworth R. Class size, class composition, and the distribution of student achievement. Education Economics. 2014;22(2):141-165. Accessed on March 30, 2016
Brookings-Chingos 2011 - Chingos MM, Whitehurst GJ. Class size: What research says and what it means for state policy. Washington, DC: Brookings Institution; 2011. Accessed on March 30, 2016
Burch 2010* - Burch P, Theoharis G, Rauscher E. Class size reduction in practice: Investigating the influence of the elementary school principal. Educational Policy. 2010;24(2):330-58. Accessed on December 7, 2015
Cho 2012* - Cho H, Glewwe P, Whitler M. Do reductions in class sizes raise students' test scores? Evidence from population variation in Minnesota's elementary schools. Economics of Education Review. 2012;31(3):77-95. Accessed on March 30, 2016
CPE-Class size 2005 - Center for Public Education (CPE). Class size and student achievement: Research review. 2005. Accessed on March 30, 2016
Ding 2010* - Ding W, Lehrer SF. Estimating treatment effects from contaminated multiperiod education experiments: The dynamic impacts of class size reductions. Review of Economics and Statistics. 2010;92(1):31–42. Accessed on March 1, 2016
Finn 2005* - Finn JD, Gerber SB, Boyd-Zaharias J. Small classes in the early grades, academic achievement, and graduating from high school. Journal of Educational Psychology. 2005;97(2):214-23. Accessed on February 4, 2016
Harker 2004 - Harker R. Class size and student attainments: Research and strategic implementation. Massey University. 2004. Accessed on March 30, 2016
Hattie 2005* - Hattie J. The paradox of reducing class size and improving learning outcomes. International Journal of Educational Research. 2005;43:387-425. Accessed on April 3, 2016
Konstantopoulos 2011* - Konstantopoulos S. How consistent are class size effects? Evaluation Review. 2011;35(1):71-92. Accessed on February 24, 2016
Mosteller 1995 - Mosteller F. The Tennessee study of class size in the early school grades. The Future of Children. 1995;5(2):113-127. Accessed on March 30, 2016
Nye 2004* - Nye B, Hedges LV, Konstantopoulos S. Do minorities experience larger lasting benefits from small classes? Journal of Educational Research. 2004;98(2):94-100. Accessed on March 14, 2016
Reynolds 2010a* - Reynolds AJ, Magnuson KA, Ou SR. Preschool-to-third grade programs and practices: A review of research. Children and Youth Services Review. 2010;32(8):1121-31. Accessed on November 9, 2015
Watson 2013 - Watson K, Handal B, Maher M, McGinty E. Globalising the class size debate: Myths and realities. Journal of International and Comparative Education. 2013;2(2):72-85. Accessed on March 30, 2016

Citations - Implementation

ECS-Zinth 2009 - Zinth K. State policies focusing on class-size reduction. Denver: Education Commission of the States (ECS); 2009. Accessed on March 30, 2016
Ed Week-Class size 2011 - Education Week. Issues A-Z: Class size. Editorial Projects in Education Research Center. 2011. Accessed on March 2, 2016
NCSL-Early ed tracking 2016 - National Conference of State Legislatures (NCSL). 2016 Early education legislative tracking. 2016. Accessed on February 16, 2017
WI DPI-SAGE - Wisconsin Department of Public Instruction (DPI). Student achievement guarantee in education (SAGE) program. Accessed on December 12, 2015

Page Last Updated

March 30, 2016

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