Two charter school studies, two findings on effectiveness

By Nick Anderson
Washington Post Staff Writer
Monday, November 30, 2009

As President Obama pushes for more charter schools, the education world craves a report card on an experiment nearly two decades old. How are these independent public schools doing? The safest and perhaps most accurate reply -- it depends -- leaves many unsatisfied.

This year, two major studies offer contradictory conclusions on a movement that now counts more than 5,000 charter schools nationwide, including dozens in the District and Maryland and a handful in Virginia.

Margaret Raymond, director of Stanford University's Center for Research on Education Outcomes, reported in June that most charter schools deliver academic results that are worse or no better than student accomplishments in regular public schools. She relied on test data from 15 states (not including Maryland or Virginia) and the District.

Caroline M. Hoxby, a Stanford economist, reported in September that charter school students are making much more progress than peers who sought entry to those schools by lottery but were turned down. She drew on test data from New York City.

The studies have drawn fire from various quarters. They highlight the challenge of rating schools with huge differences in resources, methods and students. Research over the years has shown pluses and minuses for the charter movement, which began in Minnesota in 1991.

"The people who said this was going to be the greatest thing since sliced bread were wrong," said Robert Maranto, a University of Arkansas professor of education reform, who counts himself in that group. "The people who said it would be a calamity were equally wrong."

The National Assessment of Educational Progress, a federally funded series of tests known as the nation's report card, offers one gauge. The latest results show that fourth-graders in charter schools scored 231 in mathematics on a 500-point scale in 2009, up from 228 in 2003. Fourth-graders in regular public schools scored 239 this year, up from 234 in 2003.

Here's the comparison for eighth-graders in math: Charter school scores rose to 275 this year from 268 in 2005; regular public school scores in that time rose to 282 from 278. Reading scores for 2009 are not yet available.

Such scores are useful, researchers say, but not definitive because of variations among students in charter and regular schools. Those who come from more affluent families tend to score higher on standardized tests.

Raymond, seeking a way around that problem, devised a study to compare charter school students with those she termed "virtual twins" -- peers in regular schools of similar background. Among her findings:

-- Thirty-seven percent of charter schools had smaller gains in math than regular public schools, while 17 percent of charter schools had superior gains. Forty-six percent had no significant difference.

-- Charter schools show some positive effects in elementary and middle schools and negative effects in high schools and schools with mixed grade levels. Charter schools tend to do better the longer students are enrolled. They beat the norm in some states and lag in others. (D.C. charter schools, she found, had no significant difference compared with regular schools.)

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