Tuesday, October 20, 2009

Class Size Redux

A day after complaining about 'Think Out Loud' not getting a neutral academic to talk about the evidence, I make my opinion known in a more public forum. After reading a lot of the literature on both sides, I am convinced that the best available evidence is from Tennessee and comes down solidly on positive and significant impacts of small classes. I think I do a good job noting the diversity of findings and some criticisms of the study. But I'll let you be the judge.

Excerpts from my op-ed in the The Oregonian:

... This raises the question, should Oregonians be concerned about large sized classes? The answer is yes.

The effect of class size on student achievement is the subject of intense debate among economists and education researchers. The reason has much to do with the difficulty of isolating the effect of class size when examining average achievement differences across classes, schools, districts and states.


Studies of the data from the Tennessee experiment have found significant and persistent differences in the achievement of children in the small classrooms (13-17 students) versus the large classrooms (22-26 students). The achievement gap was even wider for disadvantaged students in inner-city schools.

Princeton economist Alan Krueger has estimated that being in a smaller class significantly improved math and reading test scores ... and this from little more than two years spent in smaller classes.

Although the experiment was conducted on kindergarten through third grade classrooms, the effects of having been in a small class remained after the children returned to larger classes in higher grades. Furthermore, the more time a student spent in a small class setting, the larger and more persistent are the gains in achievement.


Subsequent study of the original participants in the program have found improved achievement in high school and a greater propensity to enroll in college preparatory classes.The experiment wasn't perfect and it has not been replicated, but it is the best evidence available and it points clearly to class size effects. Economist Krueger has estimated that the value of the productivity gains far outweigh the additional costs to the state from class size reductions. It is curious that Oregon seeks to create a renewable energy economy through tax breaks and grants while at the same time disinvesting in the human capital of the very people who are necessary to make it possible. ...

I was pleased to see they left my little lesson on selection issues in. But one thought, can you imagine the outcry if they tried such an experiment in Oregon today? If your kid was in a 25 student 1st grade class and your neighbor's kid was in a 15 student class next door in the same school, wouldn't you be outraged - even if you were told it is for the benefit of science?

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