The city is closing Community Prep High School, the only program here designed to transition students from juvenile prisons and jails to mainstream high schools.

Launched in 2002, Community Prep works with the most struggling young people in the city, offering support and coursework for a few semesters before routing students into high schools and GED programs. On average, Community Prep students have attended seven different schools when they enter, a former director said.

The program has successfully steered many students back into high school, but it has struggled to reach all its charges. The school’s average monthly attendance this year was less than 50 percent. In the first semester of this school year, students earned only 40 percent of the course credits they attempted.

The disappointing showing is the reason that Department of Education officials have concluded the program doesn’t work, despite praise from juvenile justice advocates.

“We know better options already exist,” said spokeswoman Ann Forte.

The city runs a slate of other alternative programs, including full-time GED prep classes and Young Adult Borough Centers, which offer evening classes to students older than 17. Younger students can enroll in transfer schools, which are designed for students with very few credits or who have dropped out.

School officials point out that these other programs have higher attendance rates than Community Prep. The city’s GED Prep program, for instance, has an average attendance rate of between 65 and 70 percent. The average attendance rate at Manhattan transfer schools is 75 percent, records show.

Still, many of those other options cater to different populations. For instance, one Manhattan transfer school, Harvey Milk, offers a safe space for gay teenagers. And Community Prep is one of a set of programs in District 79 whose demographics, attendance and achievement data is not easily available.

Teachers and staff at Community Prep are guaranteed a job next year at other District 79 programs, school officials said. Yet staff members are still protesting the closure, arguing that other programs won’t be able to meet the unique needs of students leaving detention. They said that the school’s successes should be judged on a case-by-case basis.

“There is nothing in place in the larger system to help [students] deal with re-entry into society,” said one teacher who asked not to be named. “How about this? How about you have a kid who finally comes to school because he finally learned how to read?”

Ana Bermudez, Community Prep’s former co-director, said that the school’s status as a temporary, non-diploma granting program may have hurt it.

“We could only keep them three semesters at most, and that was not going to be enough,” she said. “They were either checking out in advance, saying, ‘Why do I get attached to this place if I’m going to have to leave?’ Or they were nervous already about what it was going to be like to go back to another school.”

A 2004 New York Times profile of Community Prep offers a detailed portrait of the school’s successes and its struggles. That year, 10 students progressed enough to return to traditional high schools. But 16 students were re-arrested that year and another 20 dropped out.

In spite of its name, the city considers Community Prep  a “program” rather than a school under the its District 79 alternative schools office. That means the city does not have to go through the normal public approval process required when it shuts down schools, though Community Prep teachers said they hope to challenge that.

A teacher said that the school had already arranged for 5 students to transfer to other high schools and teachers estimated that the closure would force about 40 students to transfer before they had completed a full year at Community Prep. The school’s storefront space on Manhattan’s East Side will be used next year as a alternative school referral center and for GED Prep classes.