Some comments from the NYCED listserve:
Leonie Haimson:You can leave comments at the WaPost; Caroline Grannan of PAA was the first person I know of to note high attrition levels at KIPP schools. Even if it’s true re Whitehurst’s comments below re the mathematica study, showing comparable attrition levels at matched public schools, this ignores the fact that the low-achieving students at public schools go back into the pub. School system; while the struggling students at KIPP leave KIPP altogether; considerably enhancing their test scores.
Caroline Grannan: The supposedly "comparable" attrition is NOT comparable. Mathematica is giving out misleading information, a sin of omission.
Yes, there is high mobility at public schools serving low-income students, but the crucial difference is that public schools replace the students who leave, and KIPP schools don't. (It's not that they necessarily have a policy of not doing so, but the numbers show definitively that they simply don't.)
As the most at-risk, challenged students tend to be low-performing and high-mobility, the students who leave KIPP schools and are not replaced tend to be the lower-performing students. At public schools, students who leave are replaced with similarly high-mobility students.
A study of San Francisco Bay Area KIPP schools by SRI International showed that the schools lost 60% of their students, and that those students were consistently the lowest performers. Thus the KIPP schools wound up with only the highest-performing 40% of their students. (This study was apparently underway while I was doing my research and was released later -- it used data that I didn't have access to, giving the achievement levels of the students who left KIPP schools.)
The information about KIPP attrition also sheds a different light on the supposed "long waiting lists" that KIPP schools have -- as supposedly shown in "Waiting for Superman." If the lower-performing students are streaming out the door, as the data definitively proves, aren't there spots opening up all the time for the supposed eager hordes waiting to get into KIPP schools?
Again, Mathematica is giving out misleading information and needs to be refuted.
Study Finds High Dropout Rates for Black Males in KIPP Schools
Study Says Charter Network Has Financial Advantages Over Public Schools