Do effective teachers teach three times as much as ineffective teachers?
LINK: Gary Rubinstein's Blog
"As this statistic has been quoted by Melinda Gates recently on PBS and by Michelle Rhee in various places, including the StudentsFirst website I thought, in response to a recent post on Diane Ravitch’s blog I would investigate the source of this claim."
And he did. It's good. Sadly, his last statement is infuriatingly poignant.