NCPA - National Center for Policy Analysis

Increasing Class Sizes Can Actually Improve Student Learning

December 10, 2013

Increasing class sizes by reallocating students to the best teachers can improve student learning, says Michael Hansen, senior researcher at the American Institutes for Research.

Hansen identified three problems in public schooling:

  • The best teachers are not paid enough.
  • Not enough children benefit from good teachers.
  • Too many children have poor teachers.

One policy change, he wrote, could solve all three of the problems -- without requiring additional funds from taxpayers: enlarging the classes taught by the best teachers (and increasing their compensation).

Hansen studied 5th and 8th grade classrooms in North Carolina. His study indicated that allocating students to classrooms based on teacher effectiveness produced significant gains in student achievement:

  • Changing class sizes was more effective for 8th grade than for 5th grade. Moving more students into the classrooms of the most effective 8th grade teachers (up to 12 more students than would be in the average classroom) was the equivalent of adding two-and-a-half weeks of school.
  • Adding even less than 12 students -- up to six more than the school average -- showed math and science gains that were the equivalent of an additional two weeks of school. This is also the equivalent of removing the lowest-performing 5 percent of teachers from the classroom.

Source: Michael Hansen, "Right-Sizing the Classroom: Making the Most of Great Teachers," Fordham Institute, November 2013.


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