NEW YORK (CBSNewYork/AP) — The head of the United Federation of Teachers spoke out Thursday against Gov. Andrew Cuomo’s plan to add more charter schools.

As WCBS 880’s Rich Lamb reported, UFT President Michael Mulgrew was furious that Cuomo is proposing to up the cap on charter schools in New York state by 100.

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His remarks came following a report by a nonpartisan watchdog agency showing that New York City charter schools show lower rates of student attrition than traditional public schools, but serve fewer students with special needs.

The UFT itself also released a report that found that high-needs students including those living in homeless shelters and those who don’t speak English are underrepresented at the city’s charter schools.

“And (Cuomo) talks about an anti-creaming legislation (requiring charter schools to accept high-needs students),” Mulgrew said. “So what I heard as a teacher sitting there, was that the governor just said, ‘Look they haven’t followed the law that we passed in 2010 and let’s reward them by giving them more schools.’”

Mulgrew said before the cap is raised, charters must be forced to serve more needy kids and to explain extravagant suspension rates. He also said empty charter school seats must be placed under the control of local superintendents.

Supporters and critics of charter schools are trying to sway state legislators who will decide whether to go along with Cuomo and increase the cap.

Charter school backers said Thursday that the Independent Budget Office report shows that critics who accuse charters of inflating their test scores by forcing low-performing students out are wrong.

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“Down goes another baseless allegation against charter school educators and their students,” said Kyle Rosengrans, CEO of the Northeast Charter Schools Network. “In the face of this data, the unions and their sympathizers should apologize for years’ worth of smears on the hard work of charter school educators and their students.”

Eva Moskowitz, founder of the Success Academy chain of charters, said the IBO report “confirms what I’ve always known: Our student retention rates are better than the city’s.”

The IBO report tracked 3,000 charter school students and 7,200 students at nearby traditional public schools who entered kindergarten in September 2008.

It found that 64 percent of the charter school students were at the same school four years after starting kindergarten, compared with 56 percent at traditional public schools.

A total of 12.7 percent of the kindergartners in traditional public schools had some kind of disability requiring special services, compared with 8.9 percent at charter schools.

The UFT report compared student populations at charters and traditional public schools and found that charter school students are a less challenging group.

According to the report, for example, 9.5 percent of students at the Harlem Success Academy 2 charter school are in temporary housing — but that number is 26.7 percent at the district school that shares the same building with the Harlem Success 2.

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