Northwest Regional Comprehensive Center

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What the Research Says About Class Size Reduction

There is no evidence that minimal or arbitrary reductions in class size will improve student performance. Across the entire range of research studies on class size reduction, however, there are a few general conclusions that can be drawn about the effects of smaller classes on student performance:

  • In the primary grades, boys and girls equally benefit academically from long-term exposure to small classes
  • Minority and low-income students gain particular academic and behavioral advantages that increase the longer they are exposed to smaller classes
  • Gains from small classes in the primary grades are larger when class size is reduced to fewer than 15 students
  • Poor instructional practice continues to yield poor academic results no matter how much the class size is reduced
  • Students who have been in smaller classes throughout the primary grades retain academic gains made in multiple content areas upon return to standard-size classrooms in the upper grades

One caveat: When schools and districts designate Title II, Part A funds for class size reduction, they should also plan appropriate professional development for the teachers who will carry out the program and make necessary changes to the educational and physical contexts in which those programs will be placed.

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