Recently, Mayor Michael R. Bloomberg announced the Young Men’s Initiative, a three-year, $127 million citywide effort to help young black and Latino men further their education, get better jobs, become better fathers and leave the criminal justice system behind for good. As Mr. Bloomberg said, “The fact that more black and Latino young men end up imprisoned or impoverished—rather than in professions of their choosing—is not a fact we are willing to accept here in New York City. Not today. Not ever.”

The Young Men’s Imitative is revolutionary in its focus on addressing the root challenges facing black and Latino men. It focuses on four areas with the greatest disparities and most dire consequences: education, health, employment and the justice system.

In terms of the justice system, the challenges we face are clear. Three out of every four young men who leave Rikers Island return to Rikers Island, and nine out of 10 people incarcerated from New York City are black or Latino. In order to reverse the trend, the city will implement a variety of new programs, including moving Department of Probation offices into the community, launching a unique mentoring program that pairs probation clients with mentors, and examining city hiring practices to ensure that those with criminal convictions don’t face unreasonable barriers to employment. The mayor also wants to take complete responsibility for local youth in the delinquency system, so that our young people will no longer be sent far from home to a debilitating state system that has a 90 percent recidivism rate and costs $268,000 a year per child.

With these reforms, Mr. Bloomberg will be building on years of successfully bucking the national trend towards ever-increasing incarceration for young black and Latino men. Indeed, New York is already both one of the safest and least incarcerated cities in the country. A sober look at that dual achievement can better inform how we serve our most marginalized communities going forward.

Since the beginning of Mr. Bloomberg’s first term, the city has managed to dramatically reduce both its crime rates and the number of adults and juveniles sent to lock-ups, far outstripping state and national trends in both areas. While jail populations across New York State and the nation increased by 20 percent from 2001 to 2010, New York City’s jail population decreased by 10 percent.

Likewise, New York State’s prison population has declined substantially, a drop attributable entirely to New York City. From 2001 to 2010, the city sent 28 percent fewer people to prison, while commitments from all other New York State counties rose by 14 percent. Thanks to the city’s efforts, Governor Andrew Cuomo was recently able to close seven state prisons, saving taxpayers $72 million this year and $112 million next year.

The reductions are not coming just on the adult side. The city has also reduced by 62 percent the number of young people we commit to the state’s troubled juvenile justice system, allowing the state to announce in early June that it would close four upstate youth institutions and downsize four more. And we’re not only sending fewer young people upstate—we are also detaining fewer young people in New York City, diverting them instead into a growing continuum of alternative-to-placement programs. As a result, in March the Administration for Children’s Services was able to close the Bridges Juvenile Center (formerly Spofford Juvenile Detention Center), an outdated secure detention facility in the Bronx for young people awaiting adjudication in Family Court.

Here’s the important part: the city has shown that, as its incarcerated populations have been thoughtfully reduced, public safety has actually improved. According to the FBI’s Uniform Crime Report, New York City is the safest big city in America. While the city reduced its incarceration rate between 2001 and 2009, it also decreased violent crime by a whopping 41 percent, compared to a more modest 15 percent reduction nationally. During this time, rearrest rates for people on probation, the city’s largest alternative to incarceration, declined by 20 percent.

New York’s unique, dual success in reducing both crime and incarceration has been attributed to a number of factors, including innovative police practices, a concerted effort to eliminate poverty and one of the nation’s most robust networks of alternative to incarceration programs. We’ve taught the country that locking up African-American and Latino youth and throwing away the key is short-sighted, ineffective and expensive. While incarceration will always be an unfortunate necessity, the launch of the Young Men’s Initiative is further proof that, in New York City, it is increasingly our criminal justice system’s backstop, not its backbone.

Linda Gibbs is New York City’s deputy mayor for health and human services. Vincent Schiraldi is the city’s commissioner of probation.