Supporters of Eva Moskowitz would have us believe that she has created a national model for the education of poor black students. Her proof: Her schools have very high test scores.

But, as Gary Rubinstein points out in this post, very few of the students who start in Eva’s charter chain actually persist. The attrition rate is high. Since Eva adds and subtracts students until the third grade, the actual attrition rate may be even higher than what is reported.

He writes:

“Something that I think has not been reported widely enough is the attrition rate for Success Academy students. Success Academy opened in 2006 with 83 Kindergarteners and 73 first graders. Eleven years later there are now 17 twelfth graders set to be the first graduating class. So we know for sure that at least 56 out of the initial 73 students, which is 77%, have left Success Academy before graduating. But it is likely more than 77% attrition because Success Academy allows ‘backfilling’ in the early grades. We don’t know how many of those 17 students currently in twelfth grade were among the 73 original first graders in 2006 and likely we will never know. But even assuming that all 17 were among the original students, that is still 80% attrition. Even over an 11 year period, that amounts to about 10% attrition per year for that cohort.”

For a chain that claims to be “public,” Success Academy is very secretive about its data.