Class Size: Counting Students Can Count

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Why It Works … and When It Might Not
Changes in student and teacher behavior are believed to be a major reason why small classes work. Teachers in small classes pay greater attention to each pupil. Students in these classes experience continuing pressure to participate in learning activities and become better, more involved students. Attention to learning goes up, and disruptive and off-task behavior goes down.
Just placing another adult in the class does not achieve the same results, however. In the STAR experiment, policymakers thought that assigning fulltime paraprofessionals to assist teachers might be a low-cost alternative to reducing class size. But carefulanalysis of the STAR data has made it clear thatan aide in the classroom has no positive impact onstudent achievement or behavior.

Also, it seems that class sizes must be reduced substantiallyto achieve the benefits. There is no experimental research suggesting that any benefits are realizedby subtracting only a few children from a larger class— for example, transitioning from 28 to 25 students. Even a class of 20 students may be too large.