Teacher Effectiveness Ratings: Let’s Play Gopher Bash!

If you’ve been to game arcades, you know that most games now involve screens, joysticks, buttons, and software. One charmingly primitive game that thumbs its nose at electronic sophistication is Gopher Bash. In this game the player takes a mallet and waits over a “field” where gophers appear at random in their holes, bashing them with the mallet when they do. (A variation allows the player to stamp them with the foot when they appear.)

Currently the most interesting thing about this game is not its intrinsic goofiness, though in an arcade game goofiness is an attractive quality. More fascinating is that it inadvertently displays the governing model for teacher evaluation under NCLB (No Child Left Behind or Neglected Children Lose Brains: take your pick) and RAT (RAce to the Top).

First, there are district, state and federal officials charged with evaluating teachers based on Value Added Modeling. They have the mallets. What makes the teachers resemble a field full of gophers randomly popping up (or pushed up) for bashing is the use of  statistical “estimates of teacher effectiveness [that] are highly unstable[1]”  to rate them. One study cited in the report I have just quoted found that a third of teachers rated in the top 20% of effectiveness one year found themselves in the bottom 40% the following year. Another study found “year-to-year correlations of estimated teacher quality [range] from only 0.2 to 0.4. This means that only about 4% to 16% of the variation in a teacher’s value-added ranking in one year can be predicted from his or her rating in the previous year.” Thus, even a teacher in the top 20% one year may be set up by a statistical fluke for a bashing the following year, and there is no way to predict the lucky winners.

A number of perverse consequences ensue from VMA-based evaluation. It unintentionally rigs the game against the teachers of the students most in need of special help, as studies cited in this report show. Teachers would respond rationally to this disincentive to teach them by running away from the bashing-field. They also run away from its arbitrary and capricious labeling. Sadly to me, who have always valued collaboration with my faculty colleagues, as readers of this blog know, this kind of rating system also appears to undercut cooperation within a faculty.

Bill Gates, whose foundation supports value-added modeling and teacher evaluation based on students’ test scores, said in a recent New York Times column that these numbers should not be placed in newspapers to shame teachers. Big deal. In New York the VAM numbers are a part of the public record, so potentially arbitrary humiliation is just a click away. More shameful to me than the Gopher Bash game is how many tourists in the garden of education have forgotten that teachers are not the gophers; they are the gardeners.


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