Rick Hanushek has been arguing recently for focusing on the very least effective teachers. Hanushek has calculated that if we could replace a small number of the least effective teachers with average teachers it would make an enormous difference in student outcomes. This offers an intriguing link between research and potential policy actions as it suggests a reform path that does not require across-the-board changes in the teacher corp. I recommend Hanushek’s article in Education Next, but let me give a quick summary here.
Some teachers are enormously more effective (measured in terms of student outcomes) than others. The flip slide of this is that some teachers are unfortunately ineffective. Hanushek has taken this qualitative statement and attached numbers to it in a way that’s easy to understand.
Suppose that out of 100 teachers ranked in terms of effectiveness you could replace teacher 1 (at the bottom) with a teacher like teacher 50 (in the middle). That would be good, but would it be a little good or a lot good? What Hanushek did was compare in student outcomes in the U.S. with those in Canada and those in Finland (probably the country with the best schools in the world.) Then he calculated how much closer we’d be to the top if we replaced teacher 1 with teacher 50, teacher 2 with teacher 50, and so on. Hanushek then put this all in picture form, which I’ve swiped.
The exact answer to “Is the problem the bottom few?” depends on statistical estimates of teacher impact, so Hanushek calculates a whole range rather than a single number. At one end of the range, if we could replace teachers 1-5 with people like teacher 50 that would be all we need to catch up with Canada. At the high end of estimates, replacing teachers 1-12 would give the U.S. the best schools in the world.
Two policy thoughts:
“Replace” needn’t mean “fire a current teacher.” It might mean that, but we could also go a long way by being careful about who’s hired and who gets tenured.
Hanushek’s numbers suggest a feasible goal for local school districts. Suppose once a year a superintendent got together with her principals and said, “let’s look at who we’re making offers to and who’s already here. Out of 100 teachers, who’s the one lowest person on the list? Can we change that one, single individual?” A few years of small–but targeted–changes might make a real big difference.