Eva S. Moskowitz, the founder of the Success Academy charter school network, said on Friday that a list singling out children under the heading "Got to Go" was an anomaly and that the network did not have a practice of pushing out students it saw as difficult.
Ms. Moskowitz said that as soon as the network learned about the list, Success Academy quickly reprimanded the principal who had created it.
The list included the names of 16 students. It was created in December at the direction of Candido Brown, who had just become the principal of Success Academy Fort Greene.
Ms. Moskowitz said the school, which then went through second grade, had severe disciplinary problems. Mr. Brown previously said in an email that he believed he could not turn the school around if the 16 students remained.
Success Academy is New York City's largest charter school network and serves mostly black and Hispanic students, who perform much better on state tests than the citywide averages. The network's critics have long argued that it achieves those results in part by weeding out weak or difficult students, and the list appeared to lend some validity to those accusations.
Ms. Moskowitz, who spoke on Friday at a news conference, said that the list existed for only three days before Mr. Brown was admonished and that he changed course. Nonetheless, nine of the students on the list eventually left the school.
Parents of four of them said that school or network employees told them that the school was not right for their children and that they should withdraw. They described repeated suspensions, multiple daily phone calls and frequent demands to pick their children up from school early, which made their lives difficult and in some cases contributed to their decisions to leave.
Ms. Moskowitz, a former member of the City Council, said the fact that the network chastised Mr. Brown so quickly showed that his actions did not reflect the network's approach.
"A mistake was made here, and I take personal responsibility as the leader of this organization," she said.
"But I take credit for the fact that we acted swiftly to address the mistake, to correct his understanding and the school community's understanding," she added.