A charter school researcher says an upcoming study will clear New York City charter schools from criticism that they systematically “push out” high-needs students.

“I can say there is definitive evidence of some cities in the U.S. of ‘pushout’ and that New York City is not one of them,” said Macke Raymond, director of Stanford’s Center for Research on Education Outcomes.

That takeaway was offered by Raymond on Tuesday night as she spoke about a CREDO study that she is overseeing. Raymond said the research, comparing the performance of charter schools in 45 cities, would likely be released in October. (Raymond also warned the audience that she hadn’t verified all of the data with the New York State Education Department.)

Raymond, speaking at a panel discussion about charter schools hosted by the CUNY Institute for Education Policy, didn’t offer other details about the study or mention the cities where charter schools were found to be the worst offenders. But the finding could become another significant data point in an ongoing debate about charter schools, which have long faced criticism for serving lower percentages of students with special needs.

As director of CREDO, Raymond has been researching charter school results for more than five years. Her work includes an influential 2009 study that found a majority of charter school students in 15 states and Washington, D.C. performed as well as or worse than their peers in traditional schools.

That study also found that New York City charter schools were an exception to that trend. An update to that study, in 2013, upheld that finding and found charter schools had surpassed traditional public schools in reading gains and pulled even in math, progress that Raymond attributed in part to charter management organizations.

Raymond let the detail about her latest comparisons slip toward the end of the 90-minute discussion on Tuesday night, which included Century Foundation fellow Richard Kahlenberg, Hunter College Professor Joseph Viteritti, the state’s former charter school chief Sally Bachofer, and John Witte, a professor at the University of Wisconsin-Madison.

More broadly, panelists agreed that the city’s charter sector would continue to grow in the short term. A new state law virtually ensures that the sector will continue to add schools without past restraints around funding for space, and dozens of new schools are in the pipeline to open in the next several years.

Where there was less certainty was how Mayor Bill de Blasio will confront that growth. Viteritti said that however de Blasio has felt about charter schools in the past, he won’t be able to ignore the specifics for much longer.

In particular, Viteritti said, de Blasio needs to offer a clear plan for tackling controversial issues like how charter schools share space with traditional schools. The department has announced small changes to the way the school building space is allotted, but city officials have promised more sweeping changes to the way decisions are made about dramatic school-space changes.

“If Bill de Blasio has a better policy on co-location, which he seems to have, he needs to say what it is,” Viteritti said.

The panelists agreed that charter schools had come up short in acting as laboratories for new ideas that could be spread to other schools, as former union chief Albert Shanker first imagined charter schools. (De Blasio has spoken frequently of that vision for charter schools, too.)

But they disagreed on whether that was a bad thing. Bachofer, who reviewed hundreds of charter applications as head of the State Education Department’s charter schools office, said she was never impressed when school leaders said they prioritized intraschool partnership.

“I’d rather have a great school than a school that collaborates” but whose students aren’t being well-served, Bachofer said.

Viteritti said public schools haven’t proven to be much better at learning from one another, but he hoped that de Blasio could change that. Kahlenberg said one way they could work together is to do a better job of diversifying the city’s charter school student population, which is mostly made up of low-income black and Hispanic students. The ability to set aside seats for certain student populations in admissions lotteries, Kahlenberg said, offers “great opportunity.”