Students with special needs are less likely to leave charter schools than their counterparts enrolled at traditional public schools, according to a report released Thursday by the Independent Budget Office.

This conclusion updates and puts to rest a controversial IBO report on special education students and charter schools last year that found 80 percent of students with special needs left their charter schools after kindergarten. The charter sector immediately questioned the data and the agency was forced to clarify its findings. 

"This study clearly shows that charter schools educate and retain students of all needs better than district schools, putting to bed myths and falsehoods about charter attrition and creaming," said Jeremiah Kittredge who heads Families for Excellent Schools.

The issue of who enrolls at charter schools and how charters support children with disabilities is a hot-button issue in the charter versus district school turf fight. Privately managed charters have been accused of pushing out students with academic or behavioral problems. WNYC looked at city data in 2012 and found no overall trend in that direction, though there were some charters with very high attrition rates.   

In the new report, the agency used a broader definition of students with special needs. It also tracked the students for an additional year, from when they started kindergarten in 2008-09 through fourth grade, ending in the spring of 2013.

Among 267 students with disabilities in who started at charters, the report said almost 53 percent remained in their schools at the end of fourth grade compared to 49 percent of 914 students with disabilities who started at nearby traditional public schools. About a third of the charter kids left at some time to go to different public schools, compared to almost 40 percent of their peers at the district schools who left for other public schools. Another 13 percent of those in the charters left the public school system altogether compared to 11 of those in the regular schools.

IBO spokesman Doug Turetsky said the new report reached a different conclusion because it captured more kids, comparing the attrition rates for students with a range of disabilities such as speech impairments, multiple handicaps, autism and emotional disturbances. .

"What we did in the first report was use the metric that involved kids in full-time special needs classes," he explained. "Some time over the five years that we're looking at, D.O.E. switched to a system that counted students with any levels of disability," even if they were just pulled out a class for part of the day.

The center also confirmed its finding from a year ago that the overall percentage of children leaving charters is lower than those leaving traditional public schools. When it looked at 3,004 students who started kindergarten at charters, 64 percent remained in the schools in fourth grade. Among 7,178 kids who started kindergarten at nearby traditional public schools, 55.6 percent stayed at the schools.