Policy Factsheet

Smaller Classroom Sizes

Reasons for Policy

  • Smaller class sizes could positively affect student’s academic performance, especially for disadvantaged or minority students.1
  • Individualized attention in the elementary school years can have a positive effect on students that persists throughout their schooling.1

Community Groups

  • Local Government
  • Local School District
  • State Government

Policy Components

  • Class sizes of 17-20 students in the elementary school years, especially grades K-3
  • Consideration of ideal or reasonable class sizes for each school district
  • Use in conjunction with other school policy reforms

Desired Outcomes

  • Individualized attention for each student
  • Improved academic performance
  • Improved attitude towards school

Level of Evidence Available to Evaluate Effectiveness of Policy

For all policies we describe on this website, we have applied the Standards of Evidence as defined by Flay et al. (2005) in the Standards of Evidence document published by Prevention Science.

The effectiveness level of this policy is 1: Evidence-Based Policies Meeting Criteria for Effectiveness.

The levels of effectiveness as noted are:

  1. meets criteria for policy effectiveness (consistent, positive outcomes from at least two high-quality experimental or quasi-experimental trials using a comparison group or interrupted time series design);
  2. consistent evidence available linking policy with positive outcomes from high-quality observational studies only;
  3. insufficient evidence available for policy or policy components.

Achievable Results

On average, a smaller class size can achieve small improvements in students’ academic performance (Effect Size: 0.20).1

Community Examples

Links to Policy Examples

Be sure to check with your state, county, and municipal governments regarding potential existing laws that may impede any new policy development.


  1. Shin, IS, Chung JY (2009). Class size and student achievement in the United States: A meta-analysis. KEDI Journal of Educational Policy, 6(2), 3-19.  

  2. Flay, BR, Biglan, A, Boruch, RF, Ganzalez Castro, F, Gottfredson, D, Kellam, S, Moscicki, EK, Schinke, S, Valentine, JC, & Ji, P (2005). Standards of evidence: Criteria for efficacy, effectiveness and dissemination. Prevention Science, 6(3), 151-175.