(Guest Post by Matthew Ladner)
Want proof- here is how “9/33” charter sectors did on the 2015 NAEP 8th grade math test. First let’s look at middle and high income kids in Arizona and Colorado charters compared to the statewide averages for middle and high income kids:
Whew- would you look at that? I wonder if those AZ and CO charter school kids are getting half the funding per pupil of Massachusetts or not. Yes, right, so back on track here, those above kids are all middle and high-income, so how did low-income students far in these awful, horrible, no-good Wild West anarchist charter schools perform? I’m glad you asked:
Jay P. Greene's Blog 
Looks good, Matt. MA has almost 100,000 kids per grade altogether. Charter enrollment about 3% overall (K-12). How many FRL and non-FRL kids in CO and AZ charters in grade 8? How many Core Knowledge charters in CO and in AZ?
There are Core Knowledge charters in AZ and at one point the Hirsch folks were tracking schools by state. I don’t know of a source for student demographics by grade level
Never will you see this in the a) NYTimes, b) Washington Post, c) LATimes, d) Huffington Post, e) CNN, f) MSNBC, etc., etc.
All those folks marching in the name of ‘science’ would refuse to believe that poor kids in these backwood states of CO and AZ outperform those in the enlightened, progressive bastions of California (LA-Oakland), Illinois (Chicago), Pennsylvania (Philly), Maryland (DMV), or Virginia (DMV).
I am afraid that you are correct.