MANAGING TEACHERS….Fomer IBM CEO Lou Gerstner writes today in favor of merit pay for teachers. I don’t really know enough about the subject to have a firm opinion, although since I’ve spent my entire life in the private sector it seems like a pretty natural idea to me.

But here’s an observation. Not really a criticism either pro or con, just an observation: who’s going to do the evaluation?

This has long been a key question, of course, and the usual answer is the one Gerstner suggests: test scores plus “a wide variety of measurements of excellence, including peer and principal review.” But ask yourself: in the private sector, how do evaluations get done? Answer: by your boss.

This is where it gets interesting. With the exception of salespeople, white collar workers are very seldom evaluated using simple numerical tools like test scores. Those are sometimes part of the process, but for better or worse, the bulk of the evaluation is a subjective one made by your boss.

Now, this is obviously imperfect and sometimes unfair, but it’s the way the world works and most of the time it works tolerably well. But the reason it works even as well as it does is that most white collar workers have a boss who works fairly closely with them and sees the job they’re doing first hand.

Compare that to a typical elementary school, in which 20 or 30 teachers are managed by a single principal who sees them work at most for a few hours a year. How can a principal make any kind of reasonable evaluation based on that level of observation?

It’s not possible, and that brings me to my observation: for all the talk about the efficiency of the private sector, I can’t think of a private sector company that would allow itself to be as undermanaged as a typical public school. If my local elementary school were a part of IBM, it would probably have two or three first line managers, each managing a couple of grade levels, who would then report to the principal. These managers would spend their time actually managing: observing teachers, dealing with parents and the district office, mentoring new teachers, and evaluating performance.

But of course that’s a joke: no elementary school that I know of has this level of management. They may have aides, nurses, and special ed consultants, but the principal is the only actual manager on the schoolgrounds.

So there’s the paradox: I don’t think teachers are somehow immune from needing supervision, any more than any other white collar worker. But there’s precious little of it available, and it would cost a fortune to provide it. Private sector firms seem to think that reasonable levels of management make them better companies, but public schools don’t. Why?