On the surface, it would seem like smaller class sizes would produce better educational outcomes. Intuitively, this makes sense.

Research tells a different story, however. Research by Harvard economist Caroline M. Hoxby titled “The effects of class size on student achievement: New evidence from population variation”, The Quarterly Journal of Economics 115 :4 (2000), 1239-1285, which can be read here: http://www.economics.harvard.edu/faculty/hoxby/papers/effects.pdf makes a different conclusion. Some quotes from the study:

I identify the effects of class size on student achievement using longitudinal variation in the population associated with each grade in 649 elementary schools. I use variation in class size driven by idiosyncratic variation in the population. I also use discrete jumps in class size that occur when a small change in enrollment triggers a maximum or minimum class size rule. The estimates indicate that class size does not have a statistically significant effect on student achievement. I rule out even modest effects (2 to 4 percent of a standard deviation in scores for a 10 percent reduction in class size).

Using both methods, I find that reductions in class size have no effect on student achievement. The estimates are sufficiently precise that, if a 10 percent reduction in class size improved achievement by just 2 to 4 percent of a standard deviation, I would have found statistically significant effects in math, reading, and writing. I find no evidence that class size reductions are more efficacious in schools that contain high concentrations of low income students or African-American students.

As we in Wichita and Kansas prepare to make important decisions on school funding, let’s use research, not feelings, to make informed and rational decisions.

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