In August 2010, the Los Angeles Times ignited a firestorm of criticism when it published the value-added scores of thousands of teachers based on California standardized tests in reading and math (“Whatever Happened with the Los Angeles Times’ Decision to Publish Teachers’ Value-Added Scores?” National Education Policy Center, Sep. 6). Although the brouhaha has died down, there are several lessons to be learned.
The No. 1 lesson is that so much of the effectiveness of teachers is the direct result of the students they are assigned. Give a weak teacher a class full of Talmudic scholars and that teacher will shine. The converse is also true. Unless students are randomly assigned to teachers, which they rarely are, great care needs to be taken before drawing conclusions.
The other lesson is that it is unfair to compare teachers even in the same school unless they are assigned students with similar characteristics. Yet critics continue to say that everyone knows who the best teachers are. But what are the reasons?
Near the end of my 28-year teaching career in the Los Angeles Unified School District in the same high school, I was often given five classes of students from the inner-city who brought with them huge deficits. If a poll had been taken, I’m sure I would have been ranked low because of the difficulty of bringing these students up to grade level.
Value-added scores also are a nightmare for principals because once the data are released parents will demand that their children be assigned only to those teachers with the highest scores. Trying to explain the lack of validity to parents will not appease them.
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