When it comes to education policy and school reform, Alfie Kohn is one of the smartest people around.

And in a recent column at the Huffington Post, he takes on the absurdities that pass for school reform these days, most of which he notes, actually make things worse.

It’s a familiar list – testing kids until they “beg for mercy”, charter schools, standardized curriculums, closing schools, merit pay, firing teachers, getting rid of unions – but Kohn’s focus is on the hot reform topic of the day: “value add” teacher evaluations.

Before we run out and invest heavily in this latest fad, Kohn suggests asking three questions about the scheme.

Question 1: Does this model provide valid and reliable information about teachers (and schools)? Most experts in the field of educational assessment say, Good heavens, no. This year’s sterling teacher may well look like crud next year, and vice versa. Too many variables affect a cohort’s test scores; statistically speaking, we just can’t credit or blame any individual teacher.

Unfortunately, many of the experts who point this out tend to stop there, even though the problem runs far deeper than technical psychometric flaws with the technique. For example. . .

Question 2: Does learning really lend itself to any kind of “value-added” approach? It does only if it’s conceived as an assembly line process in which children are filled up with facts and skills at each station along a conveyor belt, and we need only insert a dipstick before and after they arrive at a given station (say, fourth grade), measure the pre/post difference, and judge the worker at that station accordingly. The very idea of “value-added measures,” not just a specific formula for calculating them, implicitly accepts this absurd model.

Question 3: Do standardized tests assess what matters most about teaching and learning? If not, then no value-added approach based on those tests makes any sense. As I’ve argued elsewhere — and of course I’m hardly alone in doing so — test results primarily tell us two things: the socioeconomic status of the students being tested and the amount of time devoted to preparing students for a particular test.

Can we etch that last part onto the desk of every school superintendent?

And why isn’t Kohn a prominent part of that Education Nation infotainment summit coming this month to a cable channel near you?