Second Study Gives Thumbs Up to N.Y.C. Charters

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Students in New York City’s charter elementary and middle schools make bigger learning gains than their regular public school counterparts in math and reading, according to the second report in five months to find good results for the independently run public schools in the nation’s largest school system.

The findings are attracting a lot of attention because they come from a Stanford University research group that issued a critical national study of charter schools last June. In that study, which looked at 2,403 charter schools in 15 states and the District of Columbia, the Center for Research on Education Outcomes, or CREDO, found that students in more than 80 percent of those schools performed the same as—or worse than—students in regular public schools on mathematics tests.

In contrast, CREDO’s new study, released Jan. 5, found that:

• On a student level, the academic advantage for charter school students amounts to an average of 2 points in reading and 5 points in math on a scale in which students’ scores across the state range, at the 4th grade level, from 430 to 775 points.

• On a school-by-school basis, 51 percent of New York City charter schools are producing academic gains in math for students that are statistically larger than students would have achieved in regular public schools. In reading, however, 30 percent of charters perform better on average than their local public alternatives.

• Black and Hispanic students, as well as struggling learners, do better on average in charter schools than they would have in their regular public schools, but charter schools do not appear to boost learning significantly for English-language learners, special education students, or students who have been held back a grade.

“I don’t think the two studies are inconsistent,” said Margaret E. Raymond, CREDO’s director. “Remember that in looking at the distribution of quality [in the previous study], we found hundreds of charter schools doing really well. What New York City provides us with is an opportunity to step back and say, how is it possible that one market can have as robust a quality sector, where in other markets they’re not able to get that kind of performance?”

Unlikely Consensus

The earlier study did not include data from any schools in New York state. Ms. Raymond said the center decided to apply the same research methodology to New York City schools in response to a request from district officials, although the New York analysis was unfunded. The researchers said they hope to integrate the data from New York, as well as from other states, into the larger study later on.

The results are being closely watched, because charter schools—which are public schools allowed to operate largely independent of many traditional school district rules—are a major focus of the Obama administration’s education plans. Federal education officials, in fact, give some points to states with charter-friendly environments in the competition for economic-stimulus funds from the $4 billion Race to the Top program.

The new findings out of New York City echo those from a study released in September by Caroline M. Hoxby, another Stanford University researcher. Using a different research strategy, Ms. Hoxby found that charter school students on average outperformed students who applied to the same schools but failed to win seats in them. She also concluded that the gains helped narrow achievement gaps between the inner-city students and their better-off counterparts in suburban Scarsdale, N.Y.

At the same time that Ms. Hoxby issued those findings, she also challenged the earlier CREDO study, saying that it suffered from a “serious mathematical mistake” that skewed the findings—a charge that the CREDO researchers later rebutted.

“Now you have two different studies using two different methods and finding consistent results,” said Robin Lake, the associate director of the Center on Reinventing Public Education at the University of Washington. “That’s pretty strong evidence that something is going on in New York City.”

But Sean F. Reardon, an associate professor of education and sociology at Stanford, said both the CREDO and Hoxby studies may be statistically flawed in the same way, although Ms. Raymond disagrees.

“While I’m not convinced that either the CREDO or the Hoxby study is definitive regarding the magnitudes of the effect,” he added in an e-mail, “the direction is likely positive.”

What’s harder to tell, he wrote, is “if the larger effect of charter schooling in [New York City] is because N.Y.C. charter schools are better than charter schools elsewhere, or if it’s because N.Y.C.’s traditional public schools are worse than traditional public schools elsewhere.”

The city’s 4th graders scored at about the national average, for both states and for a smaller number of urban school districts, on the latest National Assessment of Educational Progress tests in math.

Reasons Why

For their latest study, the CREDO researchers drew on six years of citywide data, beginning with the 2003-04 school year and ending with 2008-09, for students in grades 3-8. The study included 20,640 charter school students from 49 of the 52 charter schools in the city serving that particular age group. For each charter student, researchers created a “virtual twin” matched by race and ethnicity, family income level, special education participation, English-language status, and starting test scores.

Ms. Raymond said the math gains for charter students show up the first year a student enrolls, but reading gains take longer to materialize. Compared with their regular school “virtual twins,” students tend to lose ground in reading when they move to a charter school, but make more progress in the second and third years.

If charter schools are doing a better job in New York than they are in other places, Ms. Raymond said, it may be because the schools are more mature in that city, get more political support, undergo a stronger authorizing process, and get more backing from charter-support organizations.

“That is not something you see nationwide,” she added.

Experts said the study, in fact, points up the need for research to probe more deeply the reasons why charter schools succeed or fail.

“For national policymakers, this combination of findings suggests that there should be less attention to the question of whether charters in general are superior to traditional public schools,” Jeffrey Henig, a professor of political science and education at Teachers College, Columbia University, wrote in an e-mail, “and much more recognition of the fact that charter schools may or may not succeed, depending on state and local policy designs; authorizer practices; localized foundation support; and other state and local contextual factors that we don’t yet fully understand.”