Gabriel Arana says No Child Left Behind has given us a lot of hard numbers -- but we still don't know what they're telling us about educational outcomes:
But while rooting out bad teachers and excoriating unions for protecting them has become the cause célèbre of education reformers, this isn't simply a case of teachers' unions trying to protect their own. Since the passage of the No Child Left Behind Act (NCLB) in 2001, schools have been required to test students' progress on a yearly basis. There's been an ongoing debate not only about what exactly these tests measure but whether -- and how -- the resulting data should be used to evaluate teachers. For the first time, education-policy experts have a big heap of standardized statistics gathered over several years -- instead of a hodgepodge of sporadically taken samples -- and no one knows quite what to do with them.
