2:15 p.m. | Updated Editor’s Note: The following article has been updated to include a statement from the spokeswoman for Brownsville Collegiate school.

The chart below shows charter schools with the 10 highest attrition rates for the 2010-11 school year, as calculated by the New York City Department of Education. It includes only elementary and middle schools. For comparison purposes, we have included attrition rates for regular public schools in the same district as the charters, when available.

In cases where the D.O.E. did not calculate attrition rates by district they provided borough attrition rates.

Remember, these 10 charter schools are outliers. Citywide, the attrition rate at elementary charter schools was 10.8 percent in 2010-11 compared to 14.3 in traditional public elementary schools. Middle school attrition rates for both types of schools were more similar: 10.2 percent at the charters and 9.6 percent at district schools.

Methodology

The D.O.E. used enrollment records from October 31, 2010 to October 31 of 2011, accounting for fluctuating enrollment numbers at the start of school in September.

There are technically two different attrition rates: for grades K-4 and grades 6-7. The city did not include students in grades 5 and 8 because officials say their data system has trouble distinguishing “legitimate” elementary and middle school graduates from students who leave for other reasons. We used the K-4 rates at elementary schools and the 6-7 rates at middle schools. At schools that span grades K-8 we combined the attrition rates.

Findings

The charter schools with the highest attrition rates tend to be individual schools that are not part of larger networks. The exception is Brownsville Collegiate Charter, which is part of Uncommon Schools. Democracy Prep has since grown to a network of schools.

Experts in the field say free-standing charters often run into trouble, without a network to back them up, and some schools on our list have had their share of problems. A few had trouble keeping teachers, others underwent administrative changes, one serves a population with special needs, and one came under review for strict disciplinary policies. Charter Schools are privately managed but authorized by either the New York State Education Department, the State University of New York or the New York City Department of Education (although the city can no longer authorize new charters, because of changes in state law).

Fahari Academy Charter School, Brooklyn
Attrition Rate: 31.6 percent

Fahari Academy is a middle school in Flatbush that’s been plagued with high attrition rates since opening in 2009, and was placed on probation by the D.O.E. on August 27 of this year.

Only two members of Fahari’s faculty returned for its second year, in 2010-11. A science teacher left mid-year; unable to replace the teacher, the class had to be changed to Science Fiction.

The D.O.E. also encouraged the Brooklyn school to examine its discipline code and “no excuses” policy after the 2010-11 year, during which the school had 97 in-school suspensions and 128 out-of-school suspensions.

This year the school has a new executive director, Dirk Tillotson. He acknowledges there were early problems when the school didn’t listen to families. “It was trying to enforce very high standards on families and it wasn’t necessarily responsive to some of the pushback,” he said.

For example, the school used to require students to score a level 3 on the state math and English exams to move to the next grade. Regular city schools require a score of 2. Tillotson said many families transferred their students to other schools to avoid being held back a grade.

The school has since softened the promotional policy and it provides students more support in the form of reading specialists, tutoring and para-professionals. Tillotson he said 14 out of 17 teachers returned this fall. The school is one of a handful of charters now with unionized teachers.

New York French American Charter School, Manhattan
Attrition Rate: 29.7 percent

The New York French American Charter School opened in 2010-11, and an administrator who did not wish to be identified said the high attrition rate reflects a rocky start.

In December of 2011 the D.O.E. put the school on probation because of concerns about its financial stability, discipline code, and delinquency in producing audited financial statements. Days after being put on probation, the chair of the school’s board resigned.

Institutional turmoil is just part of what might explain the school’s high attrition rate during its first year. The administrator said there were other reasons, but that the rate has since come down.

“We have a highly international population so we have a lot of transient parents that move back and forth from Africa and from France and from other places, so that also plays into it,” the administrator said, adding that some families weren’t ready for the academic rigor of French immersion and chose to leave.

Harlem Day Charter School, Manhattan
Attrition Rate: 28.2 percent

Harlem Day opened in 2001 and struggled for years. A review by the SUNY Charter Schools Institute in 2008-09 found “no defined curriculum” and teaching that was often “ineffective.”

The school earned a D from the city on its 2010-11 progress report, when only 26 percent of its students were proficient in reading.

The Democracy Prep network took over the school in August of 2011 and it is now called Harlem Prep. This year it earned an A from the city on its progress report and Democracy Prep claims its students have already achieved the highest proficiency growth scores in English Language Arts in the state.

Harlem Link, Manhattan
Attrition Rate: 27.5 percent

Harlem Link‘s principal and founder, Steve Evangelista, noted that his school’s attrition rate is not much different from that of traditional public schools in Harlem. See SchoolBook’s report on student mobility among schools in Harlem.

The D.O.E. says attrition was 22.7 percent among all elementary schools in District Five in central Harlem in 2010-11. At P.S. 125 on West 123rd Street, for example, attrition was 31 percent. The school in our related story featuring Harlem Link, P.S. 161 on Amsterdam Avenue and West 133rd Street, had an attrition rate of 16 percent for its elementary pupils.

Harlem Link is technically located in District Three, which includes the Upper West Side and has a lower overall attrition rate. Evangelista said it is more accurate to compare his school to District Five schools because many of his students hail from the district.

Harlem Link struggled academically for a few years, earning a D from the city in 2010 and a C in 2011. This was partly why SUNY’s Charter School Institute gave the school a three-year renewal, instead of a five-year renewal. The school’s test scores have since gone up.

Evangelista said many of the school’s fourth graders leave to attend middle schools that start in fifth grade. As at other charters, he concedes some parents don’t like Harlem Link’s strict rules, which require students to wear uniforms or risk missing recess. Students can also be held back a grade if they don’t meet promotion criteria.

Evangelista said his school has tried to reduce student attrition by working harder to explain its policies to families before their children even start school in August. So far, he says, this tactic is paying off.

“We held over over 15 percent of our kids last year,” he said. “And this year. two-thirds of those kids returned. So we had a 33 percent attrition rate for holdovers. The year before we had a 50 percent attrition rate for holdovers. So we’re doing something better about retaining those kids.”

Democracy Prep, Manhattan
Attrition Rate: 23.7 percent

This attrition rate is for Democracy Prep’s first middle school, which opened in 2006 in central Harlem.

Founder and superintendent Seth Andrew says strict promotion criteria have led to high attrition. In regular city schools, students are almost always promoted to the next grade if they pass the state’s math and reading tests at level 2. But at Democracy Prep, students who pass the exams at level 3 can still be held back if their course average falls below 70 percent, or if they are frequently absent.

Andrew said the biggest percentage of attrition comes from “families who say ‘you know what, I can be promoted down the block at a regular district school and you’re going to hold me back a year.’”

He said the school believes in its higher standards, however, and that its approach is paying off with high test scores. Democracy Prep now has three schools and also runs Harlem Prep. Andrew said his teachers try to communicate to families that “being retained is not a bad thing. It’s an opportunity to do a grade two times” and that their child is more likely to succeed in high school and college if they master the material for each grade.

Staten Island Community Charter School
Attrition Rate: 22.7 percent

Staten Island Community Charter School opened in 2010, and is a small elementary school on the borough’s north shore.

The school did not get back to us despite repeated phone calls.

Merrick Academy Charter School, Queens
Attrition Rate: 22.6 percent

Gerald Karikari, Merrick Academy’s board chairman, says that parents are prone to take their children out of the K-6 school early in order to get better placement in a middle school.

“The problem has been not enough slots available for 7th graders,” in the Queens Village area, Karikari said. “We wind up having a graduating class of 6th graders, but also 5th graders who leave the school in advance because they want to get a 6th grade spot, which is where most of the junior high schools start.”

Karikari said things might be different if Queens schools offered as many junior high options and seats as those in Brooklyn or the Bronx. “Parents feel like if they don’t get their kids on the bandwagon now, they’ll potentially be left out later.”

The school also suffered academically. It earned an F from the city on its annual report card in 2010-11, after previously scoring a C. Several teachers had also been fired over the previous summer. Teachers voted to unionize in 2007 and the United Federation of Teachers accused the school of dragging its feet on a contract.

South Bronx Charter for International Cultures and the Arts
Attrition Rate: 20.7 percent

Principal Evelyn Hey said the school’s high attrition rate was due in part to students being accepted to the school during the lottery process, but then opting to go somewhere else.

“What often occurs is families will submit their applications to various charter schools as well their zoned public school,” Hey wrote in an e-mail. “They register in the various schools once chosen, and in September make the determination of what is most convenient for them. This results in an automatic discharge for the school although the student has never attended class.”

The elementary school is split into two sites, which Hey said was challenging for families coordinating drop-off and pick-up. She also cited families’ reliance on public transportation as a contributing factor, since some live beyond the 5-mile radius for busing.

South Bronx Charter was touched by a scandal in 2009. Its politically connected former chairman, Richard Izquierdo Arroyo, who is the grandson and chief of staff of Assemblywoman Carmen Arroyo, resigned after he was charged with embezzling funds from a non-profit housing group.

Brownsville Collegiate Charter School
Attrition Rate: 20.5 percent

Brownsville Collegiate Charter School belongs to the Uncommon Schools network, which has charter schools in Boston and Newark in addition to New York City, Troy and Rochester.

“We work very hard with families to keep all of our students,” a school spokeswoman said. “A number of our students left because they moved outside the district or state. In addition, because we opened in 2009-2010 (the first year of data represented here), the small handful of students who left in our first two years represented a bigger percentage than they would have at a fully-grown school with more students. As our school grows bigger, and parents come to understand our school and track record better, that attrition rate will go down. For the 2011-12 school year, our attrition was cut in half to 10 percent.”

John W. Lavelle Preparatory, Staten Island
Attrition Rate: 20.3 percent

John W. Lavelle Prep was created to serve students with special needs and about a third of its pupils have some form of disability.

“One of the challenges that we have is that parents who have a very broad range of kids with special needs see us as a beacon of hope, and we’re not the school for every special needs kid,” said the school’s president, Ken Byalin.

Lavelle Prep works with students who are performing below grade level. But unlike other schools, Byalin said it won’t take students with special needs who require modified promotional criteria.

“You may have been in a regular elementary school where you could get promoted if you did 10 percent of the work rather than 60-65 percent of the work,” Byalin said. But he said he needs to prepare students for college.

“We try to make it clear to parents that if you’re coming in three years behind in reading in 6th grade, the chances of moving on to 7th grade in one year are not great. It’s not impossible, but most kids that far behind, many kids will take two years to do it.”

Byalin also noted that his attrition rate is comparable to that for Staten Island. The borough’s attrition rate was 20.6 percent in the 2010-11 school year.