Judging Teachers (Yet Again)

A teacher’s “value-added” is defined as the average test-score gain for his or her students, adjusted for differences across classrooms in student characteristics (such as their previous scores).Is teacher value-added a good measure of teacher quality?

That is the question three economists asked in a study, “The Long-term Impact of Teachers: Teacher Valued-Added and Student Outcomes in Adulthood.”  A study that got quite a bit of media attention, but made me simply sigh because yet again the focus on good and bad teachers is all about students’ test scores.  And so my answer to their question (based on my firsthand experience which is nothing like their number-laden data) is: no, no, no.

Their answer, of course, is the opposite of mine. And what to do about it, in their opinion, is to focus on what isn’t working rather than what is; in other words, fire as soon as possible the dead wood. From the Times article:

The authors argue that school districts should use value-added measures in evaluations, and to remove the lowest performers, despite the disruption and uncertainty involved.

“The message is to fire people sooner rather than later,” Professor Friedman said.

Professor Chetty acknowledged, “Of course there are going to be mistakes — teachers who get fired who do not deserve to get fired.” But he said that using value-added scores would lead to fewer mistakes, not more.


For a superb response to this see Maria Bustillos‘s “The Evil Economics of Judging Teachers” (via @JBell).


Filed under In the Classroom

2 responses to “Judging Teachers (Yet Again)

  1. Ridiculous! I wonder if Prof Chetty would be so cavalier if we started talking in an offhand way about firing economists.


  2. How timely your post, just after Mayor B’s speech about pushing merit pay for teachers yesterday, an issue that pushes all the buttons in this retired teacher’s soul. If they expect teachers to advocate for students, merit pay is just about the worst idea they’ve come up with, because of the problems it creates re: how to evaluate a good teacher. Merit pay would promote all that can possibly go wrong in public schools, pitting teacher against teacher, making teachers resistant to having low-scoring students in their classes, encouraging “sucking-up” to administrators and teacher-evaluation committees, fostering fear, selfishness, and secretiveness among teachers instead of cooperative working together on behalf of their students—not to mention elevating the significance of the already way-too-almighty test score, which in turn encourages students to cheat and teachers/principals to tamper with scoresheets. When teachers are fearful of losing their jobs, their focus changes from what is best for their students to what is best for themselves. How can officials who make these decisions not see this?


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