More on the new “charters surpass traditional public schools” study


by David Safier

A few days ago I posted briefly about a study indicating that charters have improved relative to traditional public schools. I put it up quickly, before I had a chance to look over the study, because it’s by a reputable research organization at Stanford, and because I try to represent accurately what’s going on in education, not what I think should be going on. But I also said the average increase in achievement charters showed in the study — the equivalent of 8 days extra instruction in reading and no difference in math compared to traditional public schools — is relatively small. It’s much less than the variation from school to school.

I still haven’t had a chance to read over the study myself, but others have. Here’s a word of warning: if you’re a charter school supporter in Arizona, don’t go bragging about the study. Arizona is one of 8 states where charters underperformed traditional public schools (in 11 states charters outperformed traditional public schools, and the results were mixed in the remaining states). The average Arizona charter students scored as if they had 22 fewer days of instruction in reading and 29 fewer days of instruction in math than students at Arizona’s traditional public schools. That’s a significant difference.

There are a number of possible reasons why Arizona’s charter schools underperform compared to traditional public schools on average. Since the study attempts to match similar students in the schools, it’s not a difference in the economic or racial makeup of the schools. One possible reason: Arizona is the Wild West of charter schools, where pretty much anyone with a pulse and an application can open a charter school, and most charters stay open no matter how bad they are. In Arizona, only 6% of charter schools have closed since 2009, a few points lower than the national average. Combine a low bar for opening charters with minimal state oversight which could spot bad schools and close them, and the result is, too many bad charter schools stay open, dragging down the average achievement. If some of the stinkers closed their doors, average charter school achievement would increase.

Charter supporters love to say, “Charters do a better job teaching kids than those failing ‘government schools.’ Just look at BASIS, and . . . well, look at BASIS again. Did I mention BASIS is rated one of the top schools in the country by U.S. News & World Report?” But there are just a few BASIS schools, and they cherry-pick their students, who would be top performers at any schools they attended. When you look at the larger picture, charter schools aren’t the answer. They’re an alternative, sometimes a good alternative, sometimes a bad one (kinda like traditional public schools) but they aren’t the magic bullet that will magically change education for the better.


  1. Another reason that charters underperform may be that AZ law does not require charter schools to hire certified teachers. According to Dr. David C. Berliner in “The Dangers of Some New Pathways to Teacher Certification,” certified teachers account for 60 days of additional learning when compared to non-certified. He writes, “Since the school year is 10 months long, the loss from having an under-certified teacher is 20% of an academic year. That is, students pay approximately a 20% penalty in academic growth for each year of placement with under-certified teachers.”

  2. The only study I’ve seen to address the relative quality of Arizona schools directly said, if you compare Arizona students to equivalent students in other states, our students score lower on achievement tests. So an Anglo Arizona student from a high income family will have lower achievement scores than a similar student in Michigan, a Hispanic Arizona student from a middle class family will score lower than a similar student in Louisiana, and so on. The only exception is the relatively small population of African American students in Arizona who score somewhat higher than their equivalent students elsewhere.

  3. But, you don’t know how either AZ charters or AZ district schools are performing relative to the rest of the nation, just how they are performing relative to each other.