New York City's flawed data fuels the right's war on teachers
"We know that the flawed New York City teacher ratings data that was released last week is broadly unreliable, with a high margin of error and rating teachers not just by how well their students did on tests, but by how well their students did in relation to an algorithm's sometimes unreasonable expectations of how the students would perform. That's information that's widely known and indisputable. Yet the teacher rankings are still being used to publicly vilify low-rated teachers without even a cursory investigation of whether the data's many known flaws may have made a good teacher look bad."