LA teachers respond to ratings

Los Angeles teachers rated on effectiveness by the LA Times respond to the value-added evaluations. Some teachers are pleased to be recognized as effective; others feel their hard work and commitment has been disrespected.

Here’s a link to all the teacher responses.

Many teachers do not understand value-added analysis: They think they’re being judged on students’ scores, not on whether students performed as well in their class as they did in previous years.

A few teachers raised real issues: The data may ignore team teaching, the availability of tutoring or the presence of exceptionally disruptive students who make it much harder for their classmates to progress. Teachers with very high-scoring students may not be able to show improvement.

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  1. I am a big fan of value added evaluation as one of multiple measures for assessing teachers. One of the subtle features of this system is that a teacher has to keep advanced students progressing instead of ignoring their needs as frequently happens. Unfortunately the testing on which the LA results were based does not evaluate “Advanced” students very well and the teacher complaint about the impossibility of showing improvement is justified.

    For two years I did an unauthorized, unpublicized personal rating of value added in writing in our school district based on data I had access to. Our superintendent, who knew all the teachers, could, off the top of his head, predict my statistical ranking for about 90% of the teachers. In other words there was a very high concordance between personal evaluation and test results. Also the few teachers who were so good or bad that the public praised or complained about them to the school board were at the top and bottom of the value added analysis.

  2. We don’t know that these tests are interval scales. That is, we don’t know that ten points on one end of the scale means that same thing as ten points in the middle of the scale.

    We don’t know if it is more meaingful to look at progess in terms of standard deviations or percentiles.

    We don’t know that ten points over here in one grade means the same thing as ten points over there in another grade.

    These thigns have been decided abitrarily. And so the system itself is abritrary, and perhaps even capricious.

  3. Mark Roulo says:

    we don’t know that ten points on one end of the scale means that same thing as ten points in the middle of the scale.

    Actually, we probably do know that ten points in the middle of the scale almost certainly does not mean the same thing as ten points on either end of the scale.

    Standard deviations probably make more sense here than percentile rankings, but I don’t think that this is what they use.

    -Mark Roulo