Eric Simmons, a social worker at one of the nonprofits, Bronx Community Solutions, typically manages a caseload of about 60 defendants. Some are disinterested in services, he said, but on occasion he has been able to make a meaningful difference. He recalled how one client, who had been addicted to heroin for decades and entered the program after a related arrest, had long been stymied in entering a drug-treatment program because he’d lost his only means of identification. Mr. Simmons helped him replace it and begin the recovery process. “He’s reconnected with his daughters, who had lost touch with him,” Mr. Simmons said.

Pretrial supervision is not a novel idea — cities around the country have operated programs for decades — and Miriam Popper, the executive director of the New York City program, said it benefited from their experience. “We built this program on: What does the evidence say? Can it help someone get back to court and be successful?”

Whereas programs elsewhere may monitor defendants through electronic ankle bracelets and mandatory drug-testing — prompting reformers like Michelle Alexander to warn that they “contain the seeds of the next generation of racial and social control” — New York City doesn’t incorporate either practice.

Cherise Fanno Burdeen, chief executive of the Pretrial Justice Institute, a nonprofit that advocates for reforms of pretrial practices, said that New York City is also setting a markedly different tone by employing social workers as case managers. “Treating this as a structured opportunity to provide people connections to the services in the community that they need in order to be successful is much better than a law enforcement-focused model.”

Felony theft and felony drug possession are among the most common charges faced by people admitted to supervised release. Those participants assessed as being at lowest risk of failing to appear in court are required to meet with a case manager monthly; those at highest risk are required to meet weekly, accompanied by a weekly check-in by phone. Judges are apprised of participants’ compliance as their cases proceed.

After growing quickly in the year following its citywide launch, supervised release has steadily enrolled around 400 new cases per month. The mayor’s office reports that in the program’s first three years, 89 percent of defendants made all court appearances; only 8 percent were rearrested for a felony while participating in the program.

But some remain skeptical. On one side, James Quinn, who has been a prosecutor in the Queens district attorney’s office for 41 years, maintains that the risk to public safety posed by many of the people who secure release through the program is not being given sufficient consideration. Taking into account both misdemeanors and felonies, nearly 20 percent of those on supervised release are rearrested during the program, city data show.