Who Is Running America's Charter Schools? A Data Correction
For some time now, I've been posting this graph on the blog:
This graph is incorrect, and it's my fault. Let me explain:
Last year, I made a dataset that merged the work of education researchers Gary Miron and Charisse Gulosino with a school database from the US Department of Education. The dataset was for an academic paper on for-profit charter management organizations (CMOs) that is still undergoing peer review. I used the Miron-Gulosino directory of CMOs as a base, made some changes on my own, and then combined this directory with the federal data to analyze patterns in school spending.
My co-author, Bruce Baker, made the graph above with my dataset. Unfortunately, while most of the state-level datasets used for this pie chart were correct, one -- Illinois -- was not. At the risk of going way into the weeds, what happened was that several CMOs in the Chicago area were over-counted, so that the total number of students enrolled by the CMO were multiplied by the number of different campuses in the Miron-Gulosino directory.
This is entirely my mistake: Bruce and Gary and Charisse had nothing to do with it. I apologize to them for misrepresenting their work, and I apologize to all of you for missing the error.
Here is a corrected version of this graph (click to enlarge).*
As you'll notice, the shares of students enrolled in Chicago-area charter schools -- Noble, UNO, Distinctive, etc. -- are way lower. Nobel's own annual report for 2011-12 put their enrollment at "more than 6,300," which means they and others move into the "less than 10K" category.
Which actually reinforces a point Bruce made in his post:
At least a handful of studies on high profile charter operators have yielded substantive, positive results, at least with respect to growth on narrowly measured student achievement outcomes, and in some cases on college acceptance/matriculation. Of course, even these studies, like Jersey Jazzman: Who Is Running America's Charter Schools? A Data Correction: