Friday, December 28, 2007

Bonus Prize: More Thoughts on Class Size

I'm back, hopped up on Christmas goodies, and ready to comment on class size. Skoolboy, thanks a million for skillfully steering the ship this week.

On Monday, skoolboy pointed out that the evidence on class size effects on learning is mixed. Though it's clear that reduced class size improves learning in experimental settings - see skoolboy's description of the STAR experiment or this paper by Angrist and Lavy - many studies find no effect of class size on achievement (as measured by standardized test scores). Considered alongside data from around the world, where large class sizes yield high achievement, many have concluded that class size doesn't matter much for learning.

I think they are wrong. Here's why: my ability to squeeze learning out of a class is affected by the behavior of the kids sitting next to me. If the kid next to me acts like a knucklehead, I lose out. On the other hand, you can put 35 highly motivated, well-behaved teenagers in a classroom together, and their learning is going to be minimally affected by the large class. For example, selective schools like Bronx Science have very large classes, and so do countries where kids are expected to genuflect to adults.

Edward Lazear, an economist at Stanford Business School, used this idea - that the ideal class size for learning varies by the behavior/attention span of the students - to explain the conflicting findings in class size research. The trouble is that observational studies - i.e. studies using data from the real world - are mixing together the effects of class size on very different kinds of kids. In a very nice theoretical paper, he concludes that class size matters - but that the effect of class size reduction on learning varies by the behavior of the students in it. (That paper, "Educational Production," is available here.)

Two other features of class size reduction are important to note. First, I would expect the effects of class size reduction to be larger on non-cognitive outcomes (like motivation, self-discipline, interpersonal skills, and engagement) than on test scores. And to be honest, I care as much about these outcomes as I do about test scores. Improvement in these social skills can become pathways to future learning. Second, smaller class sizes could help to keep teachers in hard-to-staff schools and in the profession overall.

But as skoolboy notes, class size reduction succeeds or fails on its implementation. Future class size reduction efforts need to learn from California's experience (skoolboy describes this here) where a class size reduction created an immediate need for thousands of new teachers. (You can read about this in Jepsen and Rivkin's report here.) They advised, "A better approach to class size reduction would have been to reduce class sizes in a subset of schools each year, starting with low-performing schools serving high-poverty populations." I agree.

6 comments:

Avichal Garg said...

If smaller classes for less well behaved students are necessary, then it seems like you could either:
a) reduce class sizes for those students
b) focus on improving behavior

Are there any studies that focus on improving behavior or how to make that happen? How do other countries manage to have classes full of students like this?

skoolboy said...

I haven't studied Lazear's paper closely, but what I don't see reflected in it is attention to the organization of instruction in the classroom. The effect of the (mis)behavior of the kid next to me on my learning is contingent on how instruction in the classroom is organized. If the class is broken into small groups, the misbehavior of a student in a group different than mine may have little consequence for my opportunity to learn. On the other hand, in whole-class instruction, if a teacher has to deal with a misbehaving student, the learning of all students in the class might be disrupted. I don't expect economists to understand much about the organization of teaching and learning, but I know that you do, eduwonkette!

Rachel said...

I wonder how many of the countries that succeed with large classes are also comfortable with "triaging" a significant number of kids out of mainstream academic classes?

Dumb Economist said...

Lazear's goal in this paper is to use a few salient characteristics of educational production to write down a simple theory of classroom learning. This model is then used to make some interesting, broad, and useful predictions that can be tested empirically.

He doesn't pretend to take into account the full range of decisions that are made in the classroom. His model could easily be extended to allow for small groups within classes--i.e. to determine the optimal size and composition of these groups--but that isn't the goal of the paper.

Besides, how can dumb economists be expected to understand the high science of teaching to big vs. small groups?

Eduwonkette: you might note that Lazear is now Chair of the Council of Economic Advisors. He is a Bush appointee, so perhaps questioning his intelligence isn't entirely out of line.

dt said...

I'm not comfortable with "triaging" troubled students. But I think we need a different paradigm. Rather than ASSUMING that we should limit the size of alternative schools, we should SEEK the right size. Our model is like prisons, expand them and teachers will dump their troubles into segragated settings. But now we're closer to the L.A. hospitals that dump their poor patients in a park. Because we fear resegregation (as if that hasn't already happened) we artificially limit capacity and deny services to kids who are emotionally incapable of functioning in our schools as they are constituted today.

After the Philadelphia teacher had his neck broken by a student on an IEP who should have been in an alternative school, the Philadelphia Inquirer and the district's investigator explained why 85% of special ed students with serious infractions do not receive consequences. The law is perfectly sensible when a school has a manageable percentage of students on IEP, but when the percentage reaches a "critical mass," assistant principals are completely overwhelmed. (In our school, our percentage approaches 40% which would not be so challenging if they didn't include so many Seriously Emotionally Disturbed) We don't love the troubled kids any less, but almost none of them make it to graduation. And this is not a rap on special ed;its just an example of one of the bigger problems we haven't addressed.

It would be different if we could divert a couple of months of spending from Iraq. Or if we had learned the lessons of Jepsen and Rivkins study of California.

Looking at international comparisons, it seems to me, or seeking changes in classroom management, is just grasping at straws. Every nation has its own sins to atone for, and we're trying to address ours in public schools. And all of our problems are made more complex by the extreme proliferation of choice. I'd pay more attention to a Canadian poet (Leonard Cohn)who wrote: "Its coming to America first, The cradle of the best and the worst. ... Its here the family is broken, and here the lonely say, the heart has got to open in a fundamental way.

Democracy is coming to the USA."

John Thompson

eduwonkette said...

hi everyone,

thanks for all of the comments - here we go:

- Avichal: There are lots of studies of the effects of intervention programs on behavior. The review listed in this article may be helpful in beginning to track them down:

http://www.edweek.org/ew/articles/2007/12/19/16social.h27.html?qs=social+skills

Why do other countries have kids who are well-behaved? The child-adult relationship here is very different than in Asia, Africa, or even in Europe. Not much schools can do about this, unfortunately.

-skoolboy: I agree that the organization of instruction is central to understanding class size effects, and Lazear doesn't go there. This is something I would like to read more about. Any good papers you can recommend on this?

- smart and cunning economist: for what it's worth, i think economists are the cat's pajamas. (see my "cool people you should know" picks ). thanks for the clarification on lazear.

- Rachel: I would attribute the large classes' functionality more to behavior - but I am certainly not an international ed expert. Anyone else want to weigh in here?

- John T: You just bought yourself a week on "How can we best serve troubled students?" - probably at the beginning of February since I will need to read.