Opinion Editorial

Monday, November 2, 1998  

Reducing Class Size Doesn't Improve Test Scores

Tomorrow voters will go to the polls. One of the most important issues of concern to them is education. Both Republicans and Democrats are outdoing each other this year trying to show who is more pro-education. In the recently passed budget, both parties supported large increases in federal education spending, with the only difference being on how precisely to spend it. Among the touted benefits of this legislation is increased federal aid to hire more teachers in order to reduce class size.

Intuitively, it certainly seems true that a teacher with fewer students will be able to devote more time to each student, thus improving the quality of teaching. However, extensive research has failed to find any relationship between class size and educational outcomes, as measured by test scores. The fact is that pupil-teacher ratios have been falling for years as have test scores. If class size were so important, we would expect the opposite result.

  • In the mid-1960s, the pupil-teacher ratio in public schools was 24.1 to 1 (see figure).

  • By the early 1990s, this ratio had fallen to just 17.3 to 1, a decline of 28 percent in class size.

  • Yet over this same period, average combined scholastic aptitude test (SAT) scores fell from 954 to 896, a decline of 58 points or 6 percent. (The SAT scale was rebased a few years ago, but these data are consistent over the period.)

In a recent paper, University of Rochester economist Eric Hanushek examined the evidence on class size in detail. He found that in 277 statistical studies on class size and student achievement, only 15 percent showed a clear positive relationship. However, 13 percent actually showed a negative relationship, the rest having results that were not statistically significant.

Hanushek also points to the Tennessee experiment in the mid-1980s in which students were randomly assigned either to large or small classes. Careful records were kept of student achievement in the various class sizes. In the end, the results were statistically insignificant except for kindergartners, who showed significant improvement in smaller classes.

Hanushek concludes that too much emphasis has been put on reducing class size and insufficient attention paid to improving teacher quality. Indeed, one reason why smaller classes have not aided student achievement is because large increases in hiring of teachers to reduce class size have forced schools to hire less qualified teachers.

Improving the quality of education is unquestionably a highly desirable goal. But putting all their efforts into lower class size may not provide voters with the payoff they hope for.

Source: Bruce Bartlett, senior fellow, National Center for Policy Analysis, November 2, 1998.

For more on Education Issues http://www.ncpa.org/pi/edu/edu7c.html

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