Another team of researchers at Stanford University has released a study finding students in New York City charter schools outperform their peers in regular public schools.
The study was conducted by the Center for Research on Education Outcomes. It looked at 49 charter schools in New York City and compared their students to "virtual twins," or kids in the regular public schools who were demographically and academically identical to those in the charters. This way they could see if charters had any effect on learning.
In 51 percent of the schools, students in charters had gains on their state math exams that were statistically larger than kids in regular public schools. In a third of the schools there was no statistical difference, and in 16 percent the students showed lower levels of learning in math.
The gains in reading weren't as large, but they were still impressive to the Stanford team. The study found 29 percent of charter schools showed statistically better gains on state exams, while 59 percent showed no significant difference, and 12 percent scored significantly lower.
If those numbers cause your eyes to blur here's another way of looking at it. Margaret Raymond, who directs the Center for Research on Education Outcomes at Stanford, says the gains were especially striking over a three-year period.
"Students are going to be about 4 scale score points better off in reading and about 15 scale score points better off in math. Those are substantial numbers."
A few more points worth noting:
-Kids who transferred into charters from regular public schools actually did worse during the first year on reading. Their scores then went up in the second and third years.
-Black and Hispanic students did statistically better overall in charters compared to what they would have learned in a traditional school.
-There was no significant difference in the scores of special education students and English Language Learners.
Raymond says she doesn't know why that happened. Nor does she know why math scores would go up more than reading. But she's seen a similar trend in other states. One hypothesis, she says, is that charters incorporate into their curriculum and into their school ethos a high value on being proficient in mathematics.
"There is an unusual part of the student culture that includes kids playing math games, kids challenging each other on their multiplication tables, putting mathematics to the words of songs," she says. These are things that can reinforce math lessons.
Raymond's findings appear - on the surface - to contradict a national study she released last year finding no statistical gains in the scores of charter school students. But she says those results varied widely in different school districts. New York City asked Raymond's team to study its charter schools after reading her national study, though the research was entirely independent. Raymond says it appears New York City is doing an exceptional job with charters and she's not sure why. She suggested the politics of mayoral control of the schools could play a factor, but she hasn't been able to compare New York to other districts with and without mayoral control.
This is the second study in a year from researchers at Stanford that found New York City's charters are outperforming students in regular public schools. The other was by Stanford's Caroline Hoxby, who concluded that the city's charters were closing the "Harlem/Scarsdale gap." But she used a different methodology.
Margaret Raymond says the fact that her group and Hoxby's reached similar conclusions "strengthens the credibility" of each approach. "The conclusion to be drawn is there is something pretty positive about the New York City charter school experience."
Of course, critics might beg to differ. Charters are publicly financed but privately managed and therefore aren't required to follow the same work rules and disciplinary procedures. They often have longer school days, too. But to those who claim the schools are "creaming" the most academically inclined students, Raymond says she sees no evidence. They might serve fewer English Language Learners, but they serve a proportionate number of special education students.
Let the debate continue.