New York’s program is no panacea to violent crime; only a few hundred teenage robbers will be in the program at any one time, all from East Harlem or the Brownsville section of Brooklyn.

Nonetheless, the city’s efforts have drawn notice; the Police Department has given presentations on its program at conferences from Monterey, Calif., to Washington, D.C.

“I’m not aware of any police department nationally coming up with the same strategy or replicating what the N.Y.P.D. has done here,” said David M. Kennedy, director of the Center for Crime Prevention and Control at John Jay College of Criminal Justice in Manhattan.

The program builds, in part, on Mr. Kennedy’s successful homicide-reduction strategy, called Operation Ceasefire, that began in Boston in the 1990s and was later implemented in scores of cities. But New York’s program has a different and more narrow focus: Juvenile offenders who live within specific neighborhood borders yet commit robberies beyond those boundaries.

Getting to Know Gangs

It is the Police Department’s own brand of tough love.

“We tell these teens, ‘You have a choice,’ ” Chief Jaffe said. “You will not victimize anyone else. If you commit a new robbery or any other crime that is going to hurt people, we are going to do anything we can when you get arrested to put you in jail. Your friends will get out. You are not getting out.”

Youths in the program are flagged in police and court databases, so if one is rearrested, the police and prosecutors will coordinate their response.

Officers who run the program said they recognized what they were up against. Of the 165 East Harlem juveniles currently in the program, 55 are members of a crew, a ganglike fraternity whose members are aligned with one housing project or another. In Brownsville, more than a dozen J-RIP youths have been shot, one fatally and another who survived his fourth shooting this past summer. Last month, a program teenager was jumped by rival gang members and stabbed three or four times. He remains paralyzed.