Here are two quotes from Diane Ravitch’s blog regarding ‘value-added’ measures of teacher quality. The second one would make me laugh if it weren’t also so sadly true…
The crux of the matter isn’t whether to use multiple measures but whether to include erroneous measures and give them undue emphasis that is harmful to teachers and – by connection – students.
Gates’ – and other reformers’ – dismissal of value-added’s problems with the “it’s just one of multiple measures” line is akin to saying, “Look, the entire ice cream cone isn’t made of cow patties; the manure is just one scoop along with three scoops of real ice cream.” Either way, you’re asking people to eat crap.
UPDATE: Just found out that Bill Ferriter made a slide of this quote. Check it out!
See also my Delicious tag VAM.