Lake Wobegon and Defining the Problem in Teacher Quality
Teacher quality seems to be the top issue in education improvement these days. If only we had better teachers, the reasoning goes, we'd get better results for students. Great teachers can help close the achievement gap, and poor teachers (particularly because they are disproportionately assigned to the neediest students) can widen it.
A lot of noise is made about the fact that teachers vary in effectiveness. Of course they do. But we have to treat this as a fundamental property of measurements of populations; in any group, any particular performance characteristic we choose to measure will vary (often, but not always, in the shape of a bell curve).
It's time to stop being shocked that most people are about average, a few people are truly outstanding, and a few people are terrible. It's time to stop being surprised that about half of teachers are below average (again, regardless of what measure we're using) and half are above average. None of these facts reflects poorly on us as a profession or serves as a justification for any particular reform—nor even creates a sense of urgency to do something. They're just commonsense reflections of fundamental properties of statistics.
We want all teachers to be above average, just like the kids in Lake Wobegon. But it's impossible for everyone to be above average. The question, then, is what we do with (or, more commonly in education, to) teachers who are average, above average, or below average. Do we fire them? Pay them more? Give them more training? Create other incentives? Create policies that change how they are evaluated?
The answers to these questions depend in large part on what we're trying to accomplish. Are we trying to get rid of a few terrible people who are hurting kids? Are we trying to reward excellence? Are we trying to attract and retain higher-caliber people? Are we trying to help the average teacher grow over time? The answers to these questions need to be clear from the outset of any reform project.