Deinonychus antirrhopus

One also suspects a curvilinear relationship at play, even with all else held constant. Surely, the incremental difference of a class size of, say, 100 versus 150 is negligible. On the other hand, one would think that going below a certain number, say 10, would actually be harmful, since one misses out on the benefits of interaction.

I don't think it's fair to charaterize MY's argument as simply saying that there are other relevant factors in learning besides class size. His point is that class size and teaching quality are not independent variables. You may as well criticize the argument that an increase in the income tax rate discourages the creation of income which will cause the total tax revenue to increase less than the otherwise expected amount. That just means that tax revenue is a multivariate process and so the insight is worthless, right?

So....one becomes a better or worse teacher as class size changes?

Further, exactly which part of Matthew's post implies this notion that class size and teaching ability are somehow correlated?

I've re-read all of Matthew's post and see nothing that I'd consider profound. Could you point out exactly what you think I'm missing (i.e., a quote).

James,

That's a good point. I was thinking the same thing. Cutting a large class to a still large class probably would have neglible effect. Also, below a certain point smaller class size might be detrimental.

I hadn't read MY's post on his own blog. I just read your excerpted portion.

"And yet, if your school expands the size of its teaching staff then, all else being equal, the new hires are going to be worse than the old hires, since the best people in the profession already had jobs."

If we have smaller classes (with the same total number of kids in the school system) we will have to hire more teachers. Assuming there is some sort of competition for teaching jobs, if we start hiring more teachers then we will have to hire some teachers who otherwise wouldn't make the cut. The teachers that we already have won't become worse because they are teaching fewer students, but the average quality of teachers will decline.

Hiring more teachers (without increasing salary or other incentives to attract them) will lower their average quality. That would tend to partially offset any benefits from decreased class sizes. That would mean that any studies comparing how children learn in small classes as compared to large classes would overstate the benefit of a class size limit.

I compared that to an analysis of the effect of a tax increase on total tax revenue. You could say that total tax revenue is a function of two variables: tax rates and of economic activity. But it is important to also note that tax rates and the amount of economic activity are not independent. It is similarly deceptive to say that student learning is a function of both class size and teaching quality without also saying that changing class sizes may affect average teaching quality.

Is that any better?

Yet, we've got voter-mandated class size restrictions in Florida, without a single extra dime to pay for them.

This is what's wrong with referendums concerning services. You can always vote your heart, and hope the other guy's going to pay for it.

I've got my own reasons for wanting smaller class size, and they've got nothing at all to do with the average student. Some kids don't actually need the interaction; I never did. Treating all kids as if they were interchangeable parts is just a little overly PC, IMO.

Sure that's better, but I don't see how that contradicts anything in my post. What you are basically saying is that not everything is equal. Again, big deal. I see nothing tricky nor profound with this.

OTOH, the work environment improves when you decrease class size. Hence, the job of teacher becomes more competitive. Also, you reduce the turnover in new teachers (anecdotally, this appears to be a problem to me).

Hence, hiring more teachers doesn't mean that you'll get less qualified teachers (though I imagine you'll pick up a few when you double the number of teachers). I met several people who were new public school teachers, but got out because the job was so hellish. In a lot of places, new teachers get the classes of the worst students. Halving class size makes that a lot less painful. A class of 15 is a lot easier to control than a class of 30.

Also, there's the matter of whether it's better for a "better" teacher to teach 30 students or a "worse" teacher to teach 15 students. I wouldn't be surprised if the second can do as good a job as the first.

A couple points:

The skills required to teach are different from and independent of the skills required to manage large numbers of people. A good teacher might not be able to manage a large classroom and so may never have the chance to employ his/her teaching skills. A good classroom manager may get a stadium-full of students to participate in what amounts to a pointless exercise.

The issue of SCHOOL size is often overlooks. In particular with regard to highschools, small schools ("small =

Hmmm...

Didn't the Supreme Court recently rule that diversity of students is a critical state interest in education. Clearly, in that case, the larger the class the better. After all, in a large class each whining minority racial and ethnic group can have more precise proportional representation!

I think it is clear that if the issue went to the Supreme Court, class sizes in the hundreds would be found to be essential for good education!

Or, alternately, the smaller schools can share the minority students to maintain the precise minority representation. Yeah, that's it.