But charters and turnarounds target the lowest performing students...

Question: What about the fact that charters and particularly turnarounds target the lowest performing kids -- which may partially explain their weak performance?

Response

• If this were so, then charters should have fared much better when I removed the highest performing half of CPS and charter schools from the analysis.  However, the difference was still substantial.  In short, there are still more public schools with low performing students than charter or turnaround schools with low performing students.  The public schools, however, got more academic growth from these students.
• The assumption of the question is incorrect.  Charters do not have the lowest attaining students; they have the lowest growth students.  If the CPS NWEA data spreadsheet is sorted by attainment and then by growth you will see that there are not as many charters at the bottom of attainment as there are at the bottom of the growth list.  This means that charters are not typically enrolling the lowest of the low attaining students. They're enrolling the highest of the low attaining students and not doing much to foster any growth in those students. In order to even attend a charter school a parent has to enter his or her child into a lottery process.  It is likely that a student whose parent is involved enough to engage that process is higher performing than students whose parents do not.  This may explain why charter attainment is not as low as its growth. They enroll students whose attainment his relatively higher that their peers. However, the data indicates that their teaching and learning is not comparable to that which occurs in Chicago's public schools.
• Turnaround schools (and charters) get their percentile ranks from a comparison to schools whose students got the same average RIT score as their students on the "pre-test." If the average AUSL score was 150, then they only compared that turnaround school to other schools across the U.S. whose average RIT scores was 150. They are being ranked in relationship to schools across the U.S. whose attainment average was the same as theirs in the pre-test. It's apples-to-apples. There is no disadvantage based on the students a school serves because they're being compared to schools with students whose attainment is the same as theirs. The charters and turnarounds had similar students to the schools they're being compared to, but they got far less growth.
• As I stated in the Op-Ed, the mantra of the charter/turnaround school choice movement has always "No excuses!"  My how things change.