Gary Rubinstein has followed the progress of the much-lauded Success Academy charter chain, supposedly the most successful in the nation. He has noted that SA graduates only a small fraction of those it admits. He estimates that about 75% are gone before graduation.

Success Academy has argued that a 75% attrition rate isn’t so bad because it is about a 11% attrition per year, compounded, which, they say, is what happens in public schools too. But I don’t think this is a valid argument. Getting into Success Academy is supposed to be like winning the lottery. The attrition rate should be miniscule if Success Academy is as good as they claim. You don’t just give away a winning lottery ticket.