Voters and politicians love class size reduction. This love affair persists in the face all evidence that class size reduction is not a sensible reform. It’s not hard to ballpark the costs of smaller classes. You need more teachers, more classrooms, etc. Roughly, cutting class size 20 percent raises costs 20 percent. Will you get better results from smaller classes? Probably, but only a very little bit better. Ain’t worth it.
Matt Chingos has taken a look at the Florida statewide class size reduction put in place last decade. Florida’s schools did improve. But then Florida made lots of other changes too. So what Chingos did was compare outcomes in schools that were required to reduce class size to outcomes in schools that already had smaller classes. His summary:
…mandated class size reduction in Florida had little, if any, effect on student achievement in math and reading. The district-level analysis, which focuses on grades six through eight, yields no statistically significant effects but does not have sufficient statistical power to rule out small positive effects. I am able to examine test scores in grades three through eight using the school-level analysis, and find no evidence of positive effects and some evidence of negative effects. In general, the standard errors are small enough that even modest positive effects can be ruled out.
Let me add one more note, based on adding some of my own calculations to Chingos research. The long-run cost of the mandated class size reduction was about $1,600 per pupil. That’s close to 15 percent of total school spending.
Our kids could use more science and less make-ourselves-feel-good in school reform.