CAP has put out a series of crude reports posing as educational research, but this must be one of the least impressive. Despite its title, “The False Promise of Class-Size Reduction,” lowering class size is only one of K-12 four reforms that, according to the Institute of Education Sciences, have been proven to work through rigorous evidence.
In this report, Chingos falsely claims that that the benefits of smaller classes, as shown by the Tennessee STAR studies, faded out over time:
“The bump in test scores after one year would be impressive if it didn’t erode over time despite the continued use of small classes.”Actually, follow up studies by Jeremy Finn reveal that students who were randomly assigned smaller classes in the early grades had significantly higher graduation and college-going rates. The gains were especially impressive for low-income students:
“For all students combined, 4 years in a small class in K–3 were associated with a significant increase in the likelihood of graduating from high school; the odds of graduating after having attended small classes for 4 years were increased by about 80.0%. Furthermore, the impact of attending a small class was especially noteworthy for students from low-income homes. Three years or more of small classes affected the graduation rates of low- SES students, increasing the odds of graduating by about 67.0% for 3 years and more than doubling the odds for 4 years.”Yet another recent study showed that students who were randomly assigned a smaller class in Kindergarten were more likely to own a home and have a 401K, more than twenty years later!!
"Students in small classes also exhibit statistically significant improvements on a summary index of the other outcomes we examine (home ownership, 401(k) savings, mobility rates, percent college graduate in ZIP code, and marital status).”Here’s another misleading statement from Chingos:
“Stanford’s Eric Hanushek compiled 276 estimates of class-size effects from 59 studies, and found that only 11 percent of these estimates indicated positive effects of smaller classes. A similar number (9 percent) were negative, with the remaining 80 percent not statistically distinguishable from zero. Princeton economist Alan Krueger argued for an alternative method of counting the estimates, but this change only increased the proportion of studies showing positive effects to 26 percent, with the majority showing either negative or insignificant effects.”Actually, when Alan Krueger examined Hanushek’s claims, he found that Hanushek had miscounted the number of studies that showed positive or negative effects from smaller classes, misclassified others, and appeared to systematically extract more “estimates” from studies that found negative effects compared to those that found positive effects:
“For the 17 studies from which Hanushek took only one estimate, for example, over 70% of the estimates indicate that students tend to perform better in smaller classes, and only 23% indicate a negative effect. By contrast, for the nine studies from which he took a total of 123 estimates the opposite pattern holds: small classes are associated with lower performance.”Here is a graph of Hanushek’s estimates from Krueger's article in The Economic Journal:
If all the studies were equally counted, Krueger found, those that showed significantly positive results from class size reduction outweighed those that had significantly negative results by more than two to one.
So what is Chingos’ main beef with class size reduction? He claims that it is too “expensive.”
Which leads to the question, compared to what? As Derek Bok, once said, “If you think education is expensive, try ignorance.”
Krueger, former chief economist of the US Treasury Department, concludes that the economic benefits of class size reduction in the early grades outweigh the costs two to one:
“At a 4% discount rate, every dollar invested in smaller classes yields about $2 in benefits.”
Another recent study of class size reduction in 8th grade by economists Thomas Dee and Martin West also found that the economic benefits of smaller classes outweigh the costs:
“Using the estimated earnings impact of these non-cognitive skills and the direct cost of a class-size reduction, the implied internal rate of return from an 8th-grade class-size reduction is 4.6 percent overall, but 7.9 percent in urban schools.”
An analysis by in the Journal of Public Health estimates that reducing is class size is one of the most cost-effective public health investments that can be made, rivaling those from vaccination, with large savings in health care and almost two years of additional life expected for students placed in smaller classes in the early grades.
Has any other K-12 education reform been shown to yield larger benefits? No.
Does the Chingos report offer any? No.
Instead, Chingos puts forward the oft-repeated but highly speculative policy proposals favored by Eric Hanushek and Bill Gates. Build better data systems, that’ll lead to more learning! Fire 5-8 percent of teachers per year; that’ll produce better gains! Put kids on computers for more virtual instruction, that’ll do the trick!
Does he provide any cost estimates of these proposals? No.
Does he provide evidence from any research study that such policies have ever yielded any educational benefits? No.
At the end of the study, the Center for American Progress thanks “The Bill & Melinda Gates Foundation for generously providing support for this paper.”
If I were Bill Gates, I’d ask for my money back.