Mercedes Schneider, who holds a Ph.D. In statistics, analyzes Patrick Wolf’s evaluation of the voucher program in Milwaukee. Wolf acknowledges that the voucher program may not have raised student achievement but claims that it increased graduation rates. This “success” was qualified by a high attrition rate. In the initial study, he said that the attrition rate was 75%, but subsequently revised it to 56%.
Dr. Schneider took a closer look at the study. In this post, she demystifies the technical jargon for non-specialists and clearly explains why the methods employed by Wolf and his associates do not offer much reassurance about the value of vouchers.
Diane Ravitch's blog 
Another great person on analysis, how refreshing. Why isn’t there more questioning on the blind studies of this subject and the failure rate of the vouchers with such a high rate of leaving? Thank you for your explanation.
George Buzzetti: I agree.
Especially refreshing when one reads all the “research” put out by the sheepskin-holding accountabully underlings of the charterites/privatizers. [Ka-ching ka-ching!] Up until recently I must confess I was guilty of lumping almost all the stats/numbers folks together as “bean counters” and folks who “knew the price of everything and the value of nothing.”
Under a recent posting on this blog on which she commented (https://dianeravitch.net/2013/04/06/methodological-laws-in-the-milwaukee-voucher-study/#comments) I apologized directly to her for my too-broad brush strokes. She graciously accepted, adding that “Some of us use our powers for good.”
Remember the Justice League of America? Wonder Woman? She had a lasso that, once it ensnared villains, worked the miraculous magic of making them speak the truth.
KrazyMathLady may not have a magical lasso but her intellect and skill in argumentation have the same effect on the accountabullies: even when they holler and protest, out comes the truth.
Even if not magic, that is still wondrous to behold, don’t you think?
🙂
“patrick wolf”