NY State already has a law requiring that they develop and implement a system using test scores to measure a teacher's "value-added." The only way to undo that law, short of a State Supreme Court ruling on its constitutionality, is to write a more recent law that says the state will not do it. This new law will correct the old law. Without this new law, the old law will stand. Unless you are certain that these value-added models will be perfected in the next year or two, you might want to reconsider your position here.

If, by miracle, value-added models are suddenly perfected, NY State can always write a new law saying they will use them. But apparently the NY state legislature, regardless of political party, learned its lesson watching things unfold in NY, the city. I guess it was a real teachable moment.

The purpose of standardized testing is supposed to be to identify students in need of more help, or remediation. Any one teacher is only responsible for the education of one cohort of students at a time. Standardized test scores at any given time, for any given group, do not clearly reflect the teaching of any one teacher. There is no quality control over the input to the system. Even if students were tested every year and the results were compared to previous years, there would still be very little information for making quality of teaching decisions. Publishing results of tests would violate the privacy of both students and teachers, as well as place a false sense of blame on the individual teacher.