By their own numbers, New York City charter schools have a tough time holding onto their principals, with nearly one in five of them heading for the door from one year to the next, according to a report released by a charter school advocacy group on Monday.
The New York City Charter School Center, a nonprofit group that supports charters, composed the report, which is a close-up look at the 136 charter schools that have sprung up across the five boroughs in the last 13 years. As the report notes, the schools still tend to be young — most have been open for four years or less. They enroll only about four percent of the city's public school students.
But their numbers are growing -- next fall, more than two dozen charter schools will open across the city -- and by 2017, the charter school center expects them to account for 10 percent of public school enrollment.
The data, which were available but had not been compiled into one comprehensive report, include some numbers that support critics' complaints about charter schools -- for instance, that they have fewer challenging students, like English-language learners and special education pupils. But the data also support the prevailing argument for charters: that they provide a desired alternative to traditional public schools, with five applicants for every available seat.
Like previous studies by researchers at Stanford, the center's report praises the city's charters for their students' positive results on the state math and English tests, which are taken annually by third through eighth graders. Last year, 69 percent of charter school students scored at the "proficient" level or higher in math, compared with 57 percent of students in traditional public schools. On the English exam, the charter school students came out ahead, but not by much.
Despite that academic success, there are staffing problems. About a third of teachers leave charter schools each year, which far exceeds the rate of 15 percent at district schools.
And in 2011, about 18 percent of charter school principals left their jobs, according to the report, which hypothesizes that the schools' reliance on young teachers and "start-up mode" struggles wear out employees after a few years.
"Right now, we don't know a lot about why we're seeing that level of attrition," said James Merriman, the center's director. "I think the interesting point is that charters have managed to prosper academically with that attrition, so it strikes me that the importance of that number is really in the fact that if you can figure out how to lower that attrition level, you have maybe the biggest lever for improving results."
The attrition "is even higher than I thought," said Mona Davids, the founder of the New York City Charter Schools Parent Association, which is supportive of charters in general but has been critical of their management.
"I'm really surprised at their honesty," she said of the center's analysis, but the fact that teachers and principals "jump ship so often makes me question the sustainability of charters."
The center's report also takes a critical look at the number of special education students and children who are not fluent English speakers who attend charter schools, figures that are significantly lower than in the district schools, as has been reported and pounded by critics.
Last year, about 6 percent of charter school students were English language learners, compared with 15 percent in traditional schools.
And although only seven charter high schools are established enough to have graduated students, they lag behind the district schools in producing graduates who are prepared for college.
In 2011, about 27 percent of citywide graduates had SAT scores and Regents exam scores high enough to qualify them as college ready, by the city's standards, compared with 10 percent of charter school graduates. And once they left high school, a slightly smaller percentage of charter school students went on to college.
Charter school advocates said they expect these numbers to improve as more charter schools expand into the high school grades.
The charter school center has also organized the data by school, which can be found on its Web site.