The Upside of Class Size Reduction

Eric A. Hanushek
Published Date: 
May 23, 2011

Class size is again in the media across the country, this time because of increases in class size related to fiscal cutbacks. Instead of discussing the achievement gains that would come from class size reduction, the current commentary has focused on the calamity for public schools that will necessarily follow from increases in class size. The discussions, while ever-tinged by politics, ignore the fact that increases are not symmetric to decreases.

The rhetoric of class size policy has been virtually constant for the decade-and-a-half before this year. If one carefully culls the research literature, it is possible to find a set of studies that conclude that achievement will improve with smaller classes. It did not take much of a sales pitch to convince parents, school officials, and legislators that everything should be done to bring class sizes down further, resulting in a steady decrease in class size. And with the help of federal stimulus funds, most districts managed to keep prior reductions, even as state fiscal conditions deteriorated. Handing out pink slips to teachers in the spring (and rescinding them later) was the perennial political maneuver to ensure that education takes small if any funding cuts.

Until now. Without further federal stimulus, and without recovery from the recession, schools have begun to feel the budget pressure for the very first time, and the obvious way to deal with any budget slowdown (or actual reduction) is to let class sizes drift up a little. But this has reinvigorated the political efforts to hold education harmless from any fiscal exigencies. This situation has led to repeated news media coverage of classrooms with students sitting in the hallways, of testimonials about how it has become impossible to teach fractions with so many students, of how ten years ago they could grade papers but no longer, of . . . . It has also led to the class size reduction lobbyists quoting back their evidence with the twist of how this is the worst thing that could happen to schools.

Why is an increase different than a reduction? When reducing class size, one must hire more teachers, which means that the school system will essentially get a random draw that is expected to yield an average teacher. But increasing class size means that some current teachers must be laid off, and here the schools have a tremendous advantage. They know how effective their teachers are, so they are not forced to lay off an average teacher. They can, in fact, lay off below average teachers.

Laying off the worst teachers would lead to dramatic improvements in student achievement. As I have described elsewhere, replacing the worst 5-8 percent of our teachers with average teachers would be expected to move student outcomes near to–if not at–the top of the international league tables for math and science performance. And this would have enormous benefits for the U.S. economy and for the students who now have greater skills when they enter the labor force.

But wouldn’t the increased class sizes offset any gains? In simplest terms, no. The evidence has been rehashed many times. The latest Brookings study, for example, concludes once again that the small class size increases from the current fiscal pressures would be virtually undetectable.

Part of the confusion and dissonance over the outcomes arises from the unwillingness (or inability) of schools to make decisions based on the effectiveness of teachers. By applying LIFO rules (last in, first out) to any dismissals, schools almost completely eliminate the chance to improve the learning of our children. Specifically, they insure that the largest number of teachers is laid off, while not affecting the average quality of the teaching force.

Moreover, the difficulties are reinforced by news media stories (which appear to be getting data from each other’s stories) that breathlessly cite classes of 45, 50, and even 60. To the extent that these reports are accurate, we might even applaud the decisions. One of the biggest problems of the class size reduction movement was that it called for laws and regulations that insisted on uniform reductions without regard to the particular classes, students, and teachers and without regard to where large classes might be appropriate and where small classes might be appropriate. With increases, school decision makers can at least avoid these damaging rules and can make the changes where they have the least impact on students.

Any such large classes are truly decisions that schools are making. To obtain a five percent savings in budget, schools must typically let average student-teacher ratios drift up by less than one student per teacher. This would put student-teacher ratios back roughly to where they were five or six years ago – larger yes, but hardly the dark ages. It certainly does not require a doubling of class sizes, as some of the media accounts might suggest. The real data show that student-teacher ratios and class sizes have been falling throughout the past decade – and the recent changes are not in any way simply a continuation of a long slide toward larger classes.

Doing the right thing does require active decision making by schools and policy makers. Some of this may become easier as legislatures in Wisconsin, Illinois, Ohio, and more revisit the rules on hiring, retention, and school decision making. But it is not automatic.