More Evidence on Charter Schools

(Photo: Alex Starr)

Writing at Slate, Ray Fisman reviews the latest research on the efficacy of charter schools.  The study focuses on students at six Boston schools that had previously demonstrated an ability to improve students’ test scores on the Massachusetts Comprehensive Assessment System.  This time, however, the researchers wanted to evaluate whether the schools really improved student outcomes or just mastered the art of “teaching to the test.” Here’s the breakdown:

The study examines the college readiness of Boston public school students who applied to attend the six charter schools between 2002 and 2008, with projected graduation dates of 2006–2013. In just about every dimension that affects post-secondary education, students who got high lottery numbers (and hence were much more likely to enroll in a charter school) outperformed those assigned lower lottery numbers. Getting into a charter school doubled the likelihood of enrolling in Advanced Placement classes (the effects are much bigger for math and science than for English) and also doubled the chances that a student will score high enough on standardized tests to be eligible for state-financed college scholarships. While charter school students aren’t more likely to take the SAT, the ones who do perform better, mainly due to higher math scores.

The upshot of this improvement in college readiness is that, upon graduation, while charter and public school students are just as likely to go on to post-secondary education, charter students enroll at four-year colleges at much higher rates. A four-year college degree has historically meant a better job with a higher salary, making a spot in one of Boston’s charter schools a ticket to a better life for many students. (We’ll presumably know in a few years whether things actually turn out that way in the longer run for the cohort the researchers are following.)

Charles L.

It would be curious to run a truly random sample and see if charter schools still outperform public schools. The way this study is set up, it seems high-aptitude students (those who sign up for the lottery) are split into two groups, charter and public schools, while low aptitude students are all placed public schools. The performance of high-aptitude students in a low-aptitude environment will of course be lower. The best way to conduct a true experiment would be to either
a) Divide ALL students, not just students who choose to take the lottery, into the two groups or
b) Set up a public school for only students with high lottery numbers.
At the end of the day, I doubt the results will be much different, but charter schools will have a slight edge. Because they are non-government run, they have less oversight and are given greater liberty to discipline children and ignore the demands of parents.



I think this study is missing the point. It's been shown before that students who APPLY to charter schools will perform better regardless. So it is great that these 6 Boston charter schools are moving their students even farther, but the real question is: how do we help the students who are not applying to charter schools? Nothing about the charter school system is beneficial to those students who do not apply and remain in the public school system and THOSE are the students who need the most help.


Winnowing-out students that tend to lower results is not a luxury that public schools have. I went to California public schools in the 70's and 80's, (admittedly in a Northern California affluent area), but the average graduation & and proficiency rates were some of the highest in the world (at the time). Then they began to cut art, music, PE, and anything they deemed non-essential, but it turns out all these "extra" elements are important for critical thinking. Testing students on their ability to solve any challenge should be the measure.