Bruce Baker has watched the evolution of the effort to create that magical metric that will identify the best and worst teachers so they may be evaluated, rewarded, warned, and/or fired. He concludes that the great “value-added and growth score train wreck is here.”

Despite the billions that Arne Duncan has thrown into them, and despite the hundreds of millions that Bill Gates has targeted on a few selected districts, they are still shockingly unreliable. Baker writes:

A really, really, important point to realize is that the models that are actually being developed, estimated and potentially used by states and local public school districts for such purposes as determining which teachers get tenure, or determining teacher bonuses or salaries, who gets fired… or even which teacher preparation institutions get to keep their accreditation?…. those models increasingly appear to be complete junk! 

He analyzes the research and experience of several districts and states.

Did it occur to anyone that none of the high-performing school systems in the world are doing this disservice to their teachers?

If we continue to use junk science to rate teachers, who will want to teach?