Leave it to The Times to highlight one part of a three-year study to support its view that "value added" is
a good way to evaluate teachers. The study, by the Bill & Melinda Gates Foundation, found that classroom observations, student surveys, professional development and test scores used together gave a more reliable rating than any measure by itself.
To have The Times' headline emphasize value-added is misleading. The study found that many factors were necessary to consider when evaluating teachers, which is exactly the stand taken by teachers groups. We teachers have a hard enough job; we don't need to overcome The Times.