10/21/2011 04:31 pm ET Updated Dec 21, 2011

My Class Size Matters

My very first day as a full-time teacher, I arrived at what was then a chaotic and dysfunctional high school to discover that my first period class had 34 students, my second period had seven, and my third period had 49 (with only 42 desks at which to seat them). While these recollections might not constitute a study on class size, let me go on record anyway and say that I was quite a bit more effective that morning with the class of seven than with the class of 49.

Class size varied just as wildly in my afternoon classes though soon the smaller classes were filled out -- students transferred to the new guy (me) by some opportunistic veteran teachers out to reduce their own burdens. The class of 49 actually did get smaller when two young men in the back of the room realized they belonged to rival gangs and started brawling with each other and then three other guys of various affiliations jumped in. I got in the middle of the melee but couldn't contain it without campus police and their batons. Afterwards, I blamed myself for the violence and its aftermath -- which resulted in the incarceration of one student who had an outstanding warrant. Maybe if I'd had a better lesson that day they would have been so engaged they wouldn't have noticed their enmity for one another. Perhaps if I'd been a more inspiring teacher they would have renounced their gang affiliations altogether. At the very least I should have seen the impending altercation and jumped in before punches were thrown.

The next day, when I apologized to the class, one girl said she was glad those boys were gone. She said that one of them used to reach up her skirt in the back of my classroom. Needless to say that didn't make me feel any better.

I worked hard over the next weeks and months and years to become the kind of teacher who can handle a big class and stop a fight before it happened. So now, if I have 35 students in my third period and the counselor wants to send me a few more, I take them. Give me 37 or 43, make it 50 if you need to. I can handle it. Send me all the discipline problems -- no problem. Because I suffer from that macho disease of some inner-city teachers -- men and women. A mixture of martyrdom and bravado and sometimes with a little narcissism tossed in, over-compensation for all those early classroom disasters we can never entirely forget. And I'm afraid that this posturing of ours has helped to bolster the rather specious claims -- backed by the ever-mangled testing data -- that the number of students in a class has no more than a negligible impact on the success of the students.

Michelle Rhee, though failing to become one herself, has suggested that the best teachers ought to have larger classes -- so that more students at a time can benefit from their excellence. She is not alone in that belief. But if the best teachers can do better with 40 than some other teachers can do with 20, shouldn't we also be asking whether those exemplary teachers can do better with 25 or 30 than they can with 40?

I would want to ask that question if it were my child in that classroom. Wouldn't you?
If we ever really want every student to succeed, how are we more likely to achieve it? By identifying the best teachers and then exploiting them, possibly beyond capacity? Or by creating ideal working conditions that all teachers can exploit for the benefit of all students?

Class size matters -- and it matters for all of us, except, perhaps for the very least effective teachers, those who are either completely incompetent or who have cynically stopped trying and whose classrooms should therefore have no students in them.

Class size matters because effective teaching, at least at the high school level, requires assigning a significant amount of meaningful work, evaluating that work and offering meaningful feedback to students in a timely manner. And the degree to which any of us can provide that diminishes as the total number of our students increases.

Class size matters because many of our high school students need at least some personal attention from their teachers and when we are assigned between 150 and 200 students throughout the day there just isn't enough time to go around.

Class size matters because student ability levels can vary wildly and require us to differentiate instruction which creates further demands on our time.

Class size matters because an overcrowded classroom sends a message to students; they know when they are being warehoused and feel the cynical shrug of an indifferent education system.

Class size matters because everything takes a little longer with a big class -- attendance and grades and all the transitions within a class period.

The question isn't whether class size matters. That it must is so obvious I'm a little embarrassed to have devoted so much space to demonstrating it. We know that a high school class of 20 is quite a bit better than it a high school class would be with one teacher and 100 students. What we might consider -- perhaps should consider -- are the thresholds at which effective instruction gets eroded. Is a class of 20 really better than a class of 25? Is the difference between 25 and 30 a meaningful one? I have had this discussion with numerous colleagues over the years and have been informed by my own experiences teaching classes of various numbers. If I were offering a hypothesis for study it would be that -- at least for high school English which I teach -- a class size between 20 and 25 is ideal, 30 to 35 is incrementally challenging but realistic, and that somewhere beyond 35 the losses start to become exponential.

I hope some of the so-called reformers and education experts will put their energies into figuring this out -- rather than concoct another formula to falsely demonstrate that class size doesn't matter find a way instead for us to maximize our effectiveness without undermining it.