Updated

Most of the public policy world is ruled by warm and fuzzy myths. Take the important issue of class size (search) and student achievement.

Florida is in the process of mandating smaller class size on the assumption, presumably, that students will learn more in smaller classes with more teacher attention. Sounds good, but is it generally true?

There have been close to 300 separate studies nation-wide on the relationship between class size and student achievement. Professor Eric Hanushek (search), an economist at the University of Rochester, reviewed these studies and discovered that only 15 percent of them suggest that reducing class size improves student learning as measured by standardized tests.

Indeed, in 72 percent of the studies reviewed, there was no statistically significant effect on measurable student achievement associated with smaller classes. Even more surprisingly, in 13 percent of the studies reviewed, student test scores actually declined as class size was reduced. In sum, a full 85 percent of all of the studies on class size and student achievement found that reducing class size did not improve student performance.

None of this should really surprise anyone since, contrary to conventional wisdom, the nationwide average class size has actually been falling for decades (it was 30 students per class in 1961 and only 23 students per class in 1998); yet there has been no overall improvement in student classroom performance nationwide as measured by standardized tests (search). In short, class size may not generally matter (or may not matter much) in terms of how your daughter or my son actually performs in public school.

But what does matter? The Thomas B. Fordham Foundation (search) has done a study that demonstrates that teacher qualifications matter far more than class size. For example, teachers who have college degrees in math, or who are math certified, have students who score significantly higher on standardized tests than "math teachers" who have not specialized, i.e., have general education degrees. This would suggest that putting additional resources into hiring more qualified teachers would produce far higher student "returns" than mandating some arbitrary class size. Indeed, if you think about it logically, more qualified teachers should teach more students, not fewer students.

Should Floridians rethink the narrowly passed teacher/pupil amendment, as even Gov. Jeb Bush has suggested? Absolutely, and for two good reasons.

One, the first time around, state voters had only the dimmest idea of the tax costs associated with the passage of that amendment. Small classes certainly do sound good (I'm a former teacher) and it is understandable how emotion can sometimes cloud collective judgment. Yet realism must trump emotionalism when it comes to educational policy.

No one should ever be asked to vote for or against a proposal in the public arena without first knowing its tax costs and whether it has a reasonable chance of achieving its objectives. Unfortunately, with respect to the class size amendment (search), Florida voters were sadly uneducated on both counts. A new referendum on that issue would likely produce a more informed and reasoned judgment.

The second reason to rethink the amendment is that if class size is not the primary determinant of student performance--and the bulk of the academic studies seem to indicate that it is not--then it makes little sense to mandate some arbitrary teacher/student ratio. Why should taxpayers fork over additional dollars to lower class size when the bulk of the evidence is that lowering class size does not improve educational performance? And why should students be the guinea pigs in still another politically driven educational experiment that will not work?

Indeed, a statewide mandate might actually worsen student performance as school districts--facing a national teacher shortage--are forced to put less experienced or less qualified teachers in (smaller) classrooms. It is difficult to understand how less qualified teachers teaching fewer students will improve educational outcomes, or why taxpayers should pay for such nonsense.

Finally, if teacher performance and teacher accountability--not class size--are important determinants of student performance, then it makes sense to scrap arbitrary mandates and re-establish the freedom of local schools to hire, promote, and hold accountable more qualified teachers. Local schools and local teachers see and serve their customers every day. They need the incentives and the freedom to adopt policies (administrative and curricular) that actually improve the educational performance of their clients. (This may, of course, include small classes in special situations). But statewide class size mandates with bottomless costs and embarrassingly poor results are not the answer.

Dom Armentano is an adjunct scholar with the Cato Institute, and lives in Florida.