by Diana Senechal
In a recent head-scratcher of an article in Education Next, economist Eric A. Hanushek puts forth the argument that effective teachers produce higher salaries in their students.
The logic? Well, according to labor data, students whose high school test performance is one standard deviation above average (that is, students at the 84th percentile) can expect to earn 10 to 15 percent more per year than the student of average achievement. Hanushek assumes, apparently, that this high performance was the result of large gains over the years (as measured by test scores). We’ll get to that in a moment.
Now, according to Hanushek, if we consider that a “high-performing” teacher (at or above the 84th percentile) produces achievement gains of 0.2 standard deviations above those of students with an “average” teacher, and if one takes into account attenuation over time, one finds that such teachers will boost their students’ collective earnings by hundreds of thousands of dollars. The figure offered for a teacher in the 84th percentile with a class of 20 students is $400,000 per year; even a teacher in the 60th percentile will raise students’ earnings by $106,000.
With all due respect to Hanushek, I find that his argument oscillates between the silly and the scary. The silly part is this: there is no evidence (as far as I know) that students in the highest percentiles in high school are those who made the greatest gains on their standardized tests over the years. In fact, I suspect that most of them did pretty well on those tests all along. The top level on many of these tests is not very high; once you reach a certain level of proficiency, your gains don’t show. Unless it can be demonstrated that these top-percentile students did indeed have the greatest gains—and that their teachers had the highest value-added scores—the argument flops.
Also, there’s no reason to assume that “high-performing” teachers—those whose students make the greatest gains—bring their students to the 84th percentile or higher. It is quite possible that the larger gains occur at lower levels. For many reasons, I suspect that they tend to cluster around the average—but whether or not that is the case, there is no indication that they continue in linear fashion up to the top.
As for the scary part, let us take the argument to its logical conclusion. Suppose teachers could “produce” higher salaries in students, and suppose the “highest-performing” teachers produced the highest salaries, on average. Wow—then you’d have a cadre of test score virtuosi churning out lawyers, CEOs, social network inventors, surgeons, and change readiness consultants by the thousands. Now, some people enjoy those professions, but not all do.
Who, then, “produces” the foresters, violinists, English professors, marine biologists, simultaneous translators, teachers, firefighters, museum guides, electricians, editors, and cabinet makers? Does this fall to the not-quite-so-high-performing teachers? If so, maybe the ultimate “effectiveness” is not entirely desirable. This does not mean, of course, that anyone should settle for so-so teaching and learning. Yet we cannot assume, across the board, that more or higher equals better.
Now, most people want a good salary, up to a certain threshold. Very few want to live in poverty, to depend on others, or to be left without choices. But beyond that threshold, many may choose a profession or job that doesn’t pay spectacularly but is otherwise rewarding. Many want to keep their job low-key so that they can do things outside of work.
I realize that that isn’t quite the point—that we are talking about the difference between those who reach a certain level of achievement in school and those who don’t—and the consequences of such a gap. But even there, many ambiguities remain. Although high achievers tend to earn higher salaries, not all do or wish to do so, nor do lower achievers (within a certain range) necessarily end up lost and impoverished.
What do teachers “produce”? If there is free will, they produce nothing. They teach, inspire, and encourage their students; they demand the best of their students; and they point to many possibilities, through the subject matter and their own examples. They help students reach a point where they can support themselves and do something they enjoy. But it is the student who takes off and does it—often making choices that confound the teachers and parents. That is how it should be. Otherwise, for all our fanfare over the Future, we would be trapped in an eternal Industrial Age, with teachers turning out remote-control dolls.
Diana Senechal’s book, Republic of Noise: The Loss of Solitude in Schools and Culture, will be published by Rowman & Littlefield Education in November 2011.