As discussed here and here, the state released the results of the 2009-2010 Grade 3-8 Math and English language arts test results last week. The focus has been on the new, higher bar for passing the tests and the resulting large drop in the percentage of students judged as proficient. Charter schools, like traditional public schools across the city, saw their much-touted proficiency gains plummet. Barbara Martinez at the Wall Street Journal did a good job of summarizing charter schools’ results in New York City. In order to give a more complete picture, I analyzed the 2009-2010 results for charters to see which schools performed best and how the schools performed compared to their traditional public school counterparts. I also posted data on individual schools below and in this spreadsheet.

PROFICIENCY

I defined proficiency in the customary way: as the proportion of students at a charter school that scored a Level 3 or higher on the ELA or math tests. In order to look at overall school performance, I averaged the proficiency rate across grade levels broken down by subject, and then took the average of both the ELA and math tests to come up with a single “proficiency” number. The schools that had the highest average proficiency rates were Harlem Success Academy, Icahn Charter School 2, the Bronx Charter School for Excellence, and the Williamsburg Collegiate Charter School. (The other two Icahn Schools also scored in the top 10 of all charter schools.) To be clear, different schools serve different grades and comparing performance across grades can be misleading.

I’ve posted a chart below that lists the average proficiency rates as well as the ELA and math proficiency rates, for every charter school that posted test results during the 2009-2010 school year. Scroll over the name of the school to find out what grades the school services, which grades were tested, and other salient information relating to the school’s performance.

Dashboard 2
Dashboard 2

PEER PERFORMANCE

I also compared average charter school performance to average traditional public school performance in neighborhoods in which there is a large cluster of charter schools. This gives a rough sense of how charters compare to traditional public schools with somewhat similar demographics. The neighborhoods I chose were the same that the UFT looked at in their analysis of charter schools: the South Bronx, Central Brooklyn, and Harlem.

Using this simple metric, I found that charters in the South Bronx, Harlem, and Central Brooklyn performed much better than their traditional public school counterparts. Average charter proficiency in all three neighborhoods was about 50% compared to 35% in traditional public schools. Charters performed significantly better in math than traditional public schools, which mirrors the trend citywide. Charter schools located in the South Bronx in particular had a proficiency rate that was around 25 points higher than that of traditional public schools in the same neighborhood. The chart below summarizes my findings.

Dashboard 3
Dashboard 3

My analysis of charter school test performance did not take into account demographics, such as the proportion of ELL or special education students or the number of students who are eligible for free or reduced priced lunch. These factors, of course, can make a significant difference in test performance.

As always, I welcome your feedback for ways that I can improve this analysis, as well as other methods that I could use to make the data more understandable.