Apologies to Ken Hirsh for temporarily usurping his role as chief charter school correspondent…

Both the New York Daily News and the New York Post are touting the high pass rates achieved by New York City’s charter school students on this year’s state math assessment.  By my count, nearly 91% of the charter school students in grade 3 through 8 scored at Level 3 or Level 4 on the state assessment, which represents a very high rate of proficiency.

Buoyed by these results—which of course pertain to schools for which he has minimal responsibility—Chancellor Joel Klein said, “Charter schools have not only closed the longstanding achievement gap between New York City and the rest of the state, they have also essentially closed the achievement gap that exists between poor, African-American and Hispanic students and their white peers.”  Hmm.  “essentially” closed?  How much wiggle room does that leave?

In the chart below, I show that the performance gap between students in charter schools and white and Asian students citywide persists at every grade level. The chart shows the average scale score on the 2009 state math assessment for NYC charter school students, and the citywide average scale score for white and Asian students.  The gap in average scale scores between charter students and citywide white students ranges from 5.4 points in grade 8 to 17.1 points in grade 5.  The gap between charter students and citywide Asian students is considerably larger, ranging from 17.3 points in grade 8 to 24.6 points in grade 5.

 charter-math

The city has not yet released the citywide standard deviations for this year’s math test, but if last year’s standard deviations are a guide, charter students are lagging behind the citywide white average by about .29 standard deviations, and behind the citywide Asian average by about .54 standard deviations. 

What about the citywide averages for Black and Hispanic students?  Students in NYC charter schools are scoring higher, on average, on the state math assessment than the average Black or Hispanic student in New York City.  Many champions of charter schools take this as evidence that charter schools are more effective than traditional public schools in promoting math achievement.  Others point out that the students who enroll and persist in charter schools are not representative of all students in New York City, and that the differences in the mix of students attending charter schools and traditional schools make it difficult to judge how much of the performance difference is due to what charter schools are doing, and how much to the characteristics of students and their families that influence both which school a child attends and how well that child performs academically. 

But one thing is clear:  By the best evidence available, New York City charter schools have not yet closed the achievement gap that exists between African-American and Hispanic students and their white and Asian peers.