About a year ago I wrote a post on the idea of using "value-added" as a tool in teacher evaluation. The Seattle Times weighed in recently with an editorial endorsing it, and encouraging "retrograde union leaders" to quit opposing attempts to link teacher evaluations to student learning. As a local union leader I cringe at being called retrograde, but I'm getting used to the Times anti-union bias. I am not opposed to looking at student progress as part of an evaluation system. That makes sense. What I do think is important is that the weight placed on any test score used for evaluative purposes must be commensurate with our confidence in the reliability of the test. In my high school last year 84% of the students met standard on the Reading HSPE, 91% passed Writing, 42% passed the Math portion, and 43% passed in Science. In Reading and Writing our students did significantly better than the state average; in Math and Science we did slightly worse. But look at those numbers. Is it really reasonable to believe that the same students that do so well in Reading and Writing are so terrible in Math and Science? Or to believe that somehow the language arts teachers in the state are far and away better teachers than their colleagues in math and science? Is it possible that the tests might not be fair? Isn't it possible that the bar has been set at the right level for Reading and Writing, and far too high for Math and Science?