As some of you may have noticed, I have tried publishing this letter before (USA Today). Fortunately, it will appear in the Chicago Sun-Times. Unfortunately it is applicable nearly everywhere in the US.
Published in the Chicago Sun-Times, April 2, 2012
Teacher-rating plan flawed
The Chicago Public Schools have decided that student test scores gains will be used as part of teacher evaluation [“Teacher ratings overhaul forges on despite lack of union approval, March 31].
Everything is wrong with this plan. A number of studies have shown that rating teachers using test score gains does not give consistent results. Different tests produce different ratings, and the same teacher’s ratings can vary from year to year, sometimes quite a bit.
In addition, using test score gains for evaluation encourages gaming the system, trying to produce increases in scores by teaching test-taking strategies, not by encouraging real learning.
This is like putting a match under the thermometer and claiming you have raised the temperature of the room.
We are all interested in finding the best ways of evaluating teachers, but using student test-score gains is a lousy way to do it.
Some sources (not published with letter):
Different tests produce different ratings: Papay, J. 2010. Different tests, different answers: The stability of teacher value-added estimates across outcome measures. American Educational Research Journal 47,2.
Vary from year to year: Sass, T. 2008. The stability of value-added measures of teacher quality and implications for teacher compensation policy. Washington DC: CALDER. (National Center for Analysis of Longitudinal Data in Educational Research.) Kane, T. and Staiger, D. 2009. Estimating Teacher Impacts on Student Achievement: An Experimental Evaluation. NBER Working Paper No. 14607 http://www.nber.org/papers/w14607;