KANSAS CITY, Mo. — At the request of his probation officer, Tyrone C. Brown came to a community auditorium here in June and sat alongside about 30 other mostly young black men with criminal records — men who were being watched closely by the police, just as he was.
He expected to hear an admonition from law enforcement officials to help end violence in the community. But Mr. Brown, 29, got more than he had bargained for. A police captain presented a slide show featuring mug shots of people they were cracking down on. Up popped a picture of Mr. Brown linking him to a criminal group that had been implicated in a homicide.
“I was disturbed,” said Mr. Brown, who acknowledges having been involved in crime but denied that he had ever been involved in a killing.
That discomfort was just the reaction the authorities were after.
Mr. Brown, whose criminal record includes drug and assault charges, is at the center of an experiment taking place in dozens of police departments across the country, one in which the authorities have turned to complex computer algorithms to try to pinpoint the people most likely to be involved in future violent crimes — as either predator or prey. The goal is to do all they can to prevent the crime from happening.
The strategy, known as predictive policing, combines elements of traditional policing, like increased attention to crime “hot spots” and close monitoring of recent parolees. But it often also uses other data, including information about friendships, social media activity and drug use, to identify “hot people” and aid the authorities in forecasting crime.
The program here has been named the Kansas City No Violence Alliance, or KC NoVA. And the message on that June night to Mr. Brown and the others was simple: The next time they, or anyone in their crews, commit a violent act, the police will come after everyone in the group for whatever offense they can make stick, no matter how petty.
Such was the case for Mario Glenn, a 28-year-old with a criminal history that includes drug trafficking and assault. After he attended a program meeting, called a call-in, last year, he was caught during a police sting to take down a group implicated in several homicides. Mr. Glenn robbed a confidential informer trying to buy a gun from him, the police said. He has been convicted, and prosecutors are now seeking the maximum 30-year prison sentence.
“We have a moral reason to do a better job at addressing violence in this community,” said Jean Peters Baker, the prosecutor for Jackson County, which includes Kansas City. “I don’t know that this will work, but we need to try.”
The use of computer models by local law enforcement agencies to forecast crime is part of a larger trend by governments and corporations that are increasingly turning to predictive analytics and data mining in looking at behaviors. Typically financed by the federal government, the strategy is being used by dozens of police departments — including Los Angeles, Miami and Nashville — and district attorneys’ offices in Manhattan and Philadelphia.
At a time when many police departments are under fire for aggressive tactics, particularly in minority neighborhoods, advocates say predictive policing can help improve police-community relations by focusing on the people most likely to become involved in violent crime.
Civil liberties groups take a dim view of the strategy, questioning its legality and efficacy, and asserting that it may actually worsen the rapport between the police and civilians.
Ezekiel Edwards, the director of the Criminal Law Reform Project of the American Civil Liberties Union, said predictive policing tended to legitimize the profiling of racial minorities who live in poor, high-crime neighborhoods, and prompted officers to enforce laws selectively.
“Our concern is guilt by association,” Mr. Edwards said. “Because you live in a certain neighborhood or hang out with certain people, we are now going to be suspicious of you and treat you differently, not because you have committed a crime or because we have information that allows us to arrest you, but because our predictive tool shows us you might commit a crime at some point in the future.”
But researchers working with the police to develop the predictive algorithms say that they can come closer than traditional detective work to figuring out who is most apt to break the law. They say criminals commit violent crimes in fairly distinctive patterns and often have similar attributes. Those include previous arrests; unemployment; an unstable home life; friends and relatives who have been killed, are in prison or have gang ties; and problems with drugs or alcohol.
In Chicago, the police have developed a “heat list” of 400 people who are considered far more likely than the average person to be involved in violent crime. Factors in compiling that list included their criminal records, social circles and gang connections. Also a factor was whether they had been victims of an assault or a shooting.
In the year since its program has been fully in place, Kansas City has had a significant decrease in homicides. The city had averaged 114 homicides a year over a four-and-a-half-decade period through 2013. And the number of murders hovered over 100 in the roughly five years before NoVA’s inception. But murders plummeted to 80 last year, a 20 percent drop from 2013. While assaults with guns also decreased last year, overall assaults increased.
Whether those changes were linked to NoVA is difficult to say, because fluctuations in crime are almost always a result of multiple factors. At the same time, a report released recently by the University of Missouri-Kansas City found that while crime decreased drastically early last year as NoVA was fully in place, the drop tapered off. It is too soon to determine if decreased crime will be a long-term trend, the report said.
In other places, the success of the algorithms has been spotty or difficult to assess.
John S. Hollywood, a senior operations researcher at the RAND Corporation, said that in the limited number of studies undertaken to measure the efficacy of predictive policing, the improvement in forecasting crimes had been only 5 or 10 percent better than regular policing methods.
The Memphis police force, a pioneer in predictive policing, has worked with the University of Memphis for about a decade to forecast crime by noting time and location of episodes and information about victims. Officers then flood those areas with marked and undercover police cars, and also increase traffic stops, the department said.
But violent crime has proved stubborn in Memphis, and the city continues to be one of the most dangerous places in the nation, according to F.B.I. data.
In Kansas City, NoVA officials gather about 30 to 40 patrol officers about once a quarter to discuss and examine intelligence gathered on the street — details not necessarily captured in official documents. The information often comes from informal conversations that officers have with people on the street about things like who is arguing and who might have committed a violent crime.
The authorities have identified about 930 people who belong to 57 criminal groups in the city, said Maj. Joe McHale, the project leader for NoVA, who also commands the Police Department’s violent crime division. And there are about 125 people whom the authorities consider central figures in those groups, he said. The Kansas City authorities say they hope that if their zero tolerance for violence message gets through to these influential figures, it will be passed on to others who listen to them.
One of those powerful individuals, according to the police, was Mr. Brown, who said he began selling drugs at 14 because he was raised in poverty by a crack-addicted single mother.
When he was first drawn into the program, said Mr. Brown, who most recently served jail time for robbery, his probation officer told him he had to go to the June meeting, which is known as a call-in.
Call-ins are central to the program. The authorities invite about 120 of the group leaders they have identified (25 to 40 usually show up) to hear from a range of officials, including the local and federal prosecutors, the police chief and the mayor.
During an August call-in, the speakers told the men that this was their last chance. Tammy Dickinson, the United States attorney for the Western District of Missouri, related the story of a man in the program who was given a 15-year prison sentence for being caught with a bullet in his pocket. Another man, she said, got 25 years for having recreational designer drugs known as bath salts and posting a photograph of himself with a gun on Facebook.
A week after the June call-in, a social worker called Mr. Brown into a meeting. He said his heart was thumping when he entered the room and saw several police officers waiting for him.
“We know that you are the head of this and of that,” Mr. Brown recalled the officers telling him. “If we can change you, you can change them.”
People who have gotten in trouble with the law often think they can keep getting away with minor offenses without serious consequences, said Mr. Brown, whose nickname, Bird, slang for a brick of cocaine, came from his drug dealing. But what resonated with him, he said, was the NoVA team saying that harsh penalties will be imposed for even petty slights once warnings have been given.
Mr. Brown has come to see some benefit in the program. NoVA officials have helped him find housing, he said, and pushed him to get a job — he now works as a delivery driver for Back Porch Bar-B-Q. The authorities connected him with a program to help him pay child support — he has four children ranging from 4 months to 7 years. And he works with young people to help keep them out of trouble.
Still, Mr. Brown is hardly in the clear. Domestic assault charges are pending against him after his girlfriend accused him of choking her and hitting her head against a door last year, according to court documents.
Shaking loose from past misdeeds can be challenging, Major McHale said.
“Sometimes you can’t get away from things that you’ve done,” he said, “even though you turned a new leaf.”