In his letter to the editor published yesterday in the New York Times, James D. Merriman sings the praises of New York State’s charter schools. Not surprising, since Merriman is Chief Executive of the New York City Charter School Center. But he also acknowledges that too many charter schools fare no better than district public schools, and sometimes fare even worse. This information comes from an influential (and controversial) study published last month by Stanford University’s Center for Research on Education Outcomes (CREDO) called Multiple Choice: Charter School Performance in 16 States.

Since charter schools play such a key role in our national reform agenda, I’ve decided to start a mini-blog-series called “Charter Schools” in which I’ll be taking a closer look at this increasingly popular alternative to traditional public schools. And what better place to start than by analyzing CREDO’s study in greater detail.

What makes CREDO’s study most unique is definitely its scope. This is the first national assessment of charter schools to present longitudinal data on student achievement using data from over 70 percent of all charter school students in the United States. (Over 1.7 million records from 2403 charter schools in 15 states and the District of Columbia were analyzed.) Further, the study’s methodology is also unique in its use of “virtual twins.” For each charter school student, a “virtual twin” is found who attends a local traditional public school and matches the charter school student on certain key variables (demographics, proficiency in English, and participation in special education or subsidized lunch programs). This enables researchers to compare charter school students’ learning gains with those of their public school counterparts.

Multiple analyses were conducted on the data yielding many different results. Here are (in my opinion) the four most significant findings:

1) Across all charter schools studied, 46 percent show no significant differences in student math gains than their traditional public school counterparts. Only 17 percent show significant math gains that exceed traditional public schools, and 37 percent actually show significantly lower gains. (In plain English, this means that in 83 percent of charter schools studied, students would have done just as well or better in math if they attended local traditional public schools instead. Or so the study suggests.)

2) Charter school effectiveness varies widely by state. Those that show significantly higher learning gains for charter schools compared to traditional public schools are: Arkansas, Colorado (Denver), Illinois (Chicago), Louisiana and Missouri. Those that show no significant differences in gains are: California, District of Columbia, Georgia, and North Carolina. And those showing significantly lower gains are: Arizona, Florida, Minnesota, New Mexico, Ohio, and Texas.

3) Differences in state charter policies are associated with differences in students’ academic success. States with charter school caps tend to show significantly lower academic growth among charter schools, as do states with multiple charter school authorizers, and those that do not provide an avenue for charter school operators to appeal adverse decisions on applications or renewals.

4) Charter schools have significantly different impacts on students with different backgrounds. Black and Hispanic students show significantly lower learning gains than their virtual public school twins, while students living in poverty and English Language Learners realize significantly higher gains in charter schools. Students in Special Education programs show no significant differences in learning gains compared to their virtual twins.

So what does all this mean? Stay tuned for tomorrow’s post where I’ll delve into an analysis of this study and of its implications.

(Photo: Conspirator’s flickr photostream/ Creative Commons)