picture-11
A chart from the CREDO study shows black and Hispanic students in charter schools have higher scores on reading and math tests than peers in district schools.

Students in nearly 50 charter schools across the city are outperforming their peers in district schools on state tests, according to a study by an education research group at Stanford University.

The report, which was done by the Center for Research on Education Outcomes, known as CREDO, uses the same methodology the group used when looking at the performance of charter schools in several states across the country. Looking at 49 city charter schools from the 2003-04 to 2008-09 school years, CREDO matched data from about 20,000 students in grades 3-8 to an identical number of students with comparable scores at local competing district schools. Though the Department of Education asked CREDO to do the analysis, the foundation procured its own funding for it.

CREDO’s study of charter schools across the country offered a mixed picture — charter schools in some states did better than local schools, while others did worse — but New York City stands out as having a particularly successful crop of charter schools.

In the city charter schools CREDO looked at, 51 percent had higher math scores than district schools, 33 percent were no different, and 16 percent had lower scores. On reading tests, 29 percent had higher scores, 59 percent showed no difference, and 12 percent had lower scores.

Charter school advocates welcomed the study, which is the second of its kind in the last several months to show charter schools outperforming district schools. In September of last year, another researcher at Stanford, Caroline Hoxby, released a study comparing students who entered and won charter school lotteries to those who entered the same lotteries but did not secure seats.

“It’s good news,” said James Merriman, who heads the New York City Charter School Center.

“I like that we’re seeing consistency in the findings. What you want to see is researchers using different methodology and seeing the same trends. I think that’s pretty rare in education research,” he said.

Among charter school critics, the report’s findings elicited common criticisms of a system that permits charter schools to admit fewer students who are not fluent in English and fewer students with severe learning disabilities than districts schools do.

“I am surprised that the charters don’t do better, given their many advantages,” said New York University education historian Diane Ravitch.

“We know they have only 111 of the city’s 51,000 homeless students. We know they have longer hours and their teachers work 50 hours a week or so. We know their sponsors add millions so they can have smaller classes and better facilities.

“Kids who go to charters have a very large chance of going to a school that is no better or worse than their public school,” Ravitch said.

Overall, the study found that charter schools are scoring about five scale score points higher in math and two points higher in reading than students in district schools. It also found that in students’ first year at a charter school, their reading scores decrease modestly, but then rebound and eventually top those of district school students in the following years.

CREDO director Margaret Raymond said charter schools may be having a harder time getting their reading scores far beyond district schools’ scores because the city has been focusing on literacy programs for years.

“There is not that sort of unified focus around math instruction,” Raymond said. “In the charter school world, and this is anecdotal, there is something in the student culture about being a math wizard. There are lots of school cultural things like contests for knowing your multiplication tables,” she said.

Columbia Teachers College Professor Aaron Pallas had another theory: “The kinds of math skills that are tested are just more responsive to test prep than reading is.”

The study also found that black and Hispanic students have higher test scores than peers in district schools, but students who are not fluent in English and special education students in charter schools are not performing any differently than those in district schools.

“We would have hoped, as everyone would hope, that charters had figured this area out,” Merriman said. “This is clearly something that charter school leaders will be looking at.”

Raymond said the group’s study did not take into account whether charter schools have smaller class sizes, more instructional time, or significantly different student populations. She also noted that because the study focuses on schools with data from state tests, newly opened schools where students are too young to have been tested were not included.

CREDO’s study “doesn’t tell us what would happen if there was a great deal of expansion of charter schools,” Pallas said. “The new schools coming on line may not be like the ones that are already there. We don’t know much about the newer charter schools and how they’re doing.”

Though there’s little chance CREDO’s study will quell debate over whether charter schools are better than district schools, the study may add another layer of support to Hoxby’s earlier findings.

“The fact that the national CREDO study was much more critical of charter schools will make this study more credible to folks,” said Columbia Teachers College Professor Jeff Henig.