There are two separate issues at play here. First, the criticism that the value added measures are statistically bankrupt is methhodologically complex, but not correct. The argument is that if you can’t randomize assignment to the experimental condition, then you can’t have valid or generalizable knowledge. That was one (of the many) arguments against the now well-accepted fact that cigarette smoking leads to lung cancer. Lack of random assignment complicates science, but here are plenty of things that can’t be randomized that we can nevertheless study.
Second, it’s also fairly clear that those who are pushing teacher rating systems do not have the best interests of teachers or even children at heart. Measurement of teacher effect is not simple, and there are many other variables involved - socio-economic factors, available resources, etc. However, I don’t think anyone on either side of his debate would argue that teachers don’t matter, and if they do matter, then it should be possible to devise a fair and valid way to evaluate teacher performance.
