A strategy that puts teams of cops on a beat, an age-old crime-fighting tactic that Boston Police Commissioner Edward F. Davis revived in Boston more than four years ago, has helped reduce the number of shootings and robberies, according to a federally funded study.
The hot spots patrolled by the teams experienced a 17 percent drop in overall violent crime since the strategy was launched, compared with 2000-2006, when the teams were not in place.
Davis assigned the teams shortly after he was sworn in as commissioner in December 2006, hoping that the officers would develop relationships with community leaders and residents, a proactive approach known as community policing.
The city has 12 Safe Street teams: groups of five officers, supervised by a sergeant, who patrol on bikes and on foot and are assigned to high-crime areas.
“You can unleash the cops, flood an area, but there is a lot of research that shows that can have backfire effects. People can be more afraid,’’ said Anthony Braga, a professor at the Rutgers School of Criminal Justice, who conducted the study along with two other academics. “The way that these teams are oriented to engage the community is much more desirable.’’
Still, the study, conducted between 2007 and 2009, showed that the teams had no significant effect on reducing the number of homicides or sexual assaults.
And internal tensions over the program remain: Supervisors have questioned why teams cannot be moved from their designated spots to other nearby streets when crime worsens there; officials complained about the set hours of the teams, saying it made them too predictable to criminals; and some teams patrolled their hot spots but did little to engage with residents.
The concept has also led to complaints from some captains who want to move the teams.
“Police really don’t like change,’’ Braga said. “Some captains who have always done things a certain way and all of a sudden you put a limitation on their sovereignty, it gets very stressful for them.’’
Captain Frank Armstrong, president of the Boston Police Superior Officers Federation, said that supervisors know their districts intimately and where officers should be placed.
“I don’t think they’re protecting their sovereignty,’’ said Armstrong, who stressed that he generally agrees with the program’s mission. “I think they’re reading the incident reports every day and they’re trying to marshal their forces in the most efficient manner possible.’’
Davis said he has given more latitude to captains whose crime statistics have improved, but that generally teams should stay put, rather than move to respond to an emerging crisis.
“Chasing our tails is not a good strategy,’’ Davis said in an interview.
In the neighborhoods where the teams have fanned out, opinions vary.
“We’re ecstatic about them,’’ said Jorge Martinez, executive director at Project RIGHT, an antiviolence organization in the Grove Hall section of Roxbury, where a Safe Street team patrols in the evenings. “They’re accessible. . . . The interaction between these police officers and the community has been incredible.’’
Martinez said the officers show up to every community meeting, discuss crime-prevention strategies with neighborhood leaders, and frequently interact with young people, even collecting prom dresses for poorer students.
But in the Bowdoin-Geneva section of Dorchester, where several recent shootings and homicides have unnerved residents, some officers are less involved, said Davida Andelman, chairwoman of the Greater Bowdoin Geneva Association.
Officers in her area tend to keep to themselves, she said, huddling together on their bicycles or sitting in their cruisers.
“I’m glad they’re visible, but they need to be engaged quite a bit more with residents and it’s unfortunate,’’ said Andelman, who has lived in the neighborhood for almost 30 years. “In the olden days, you pointed to the beat cop, that person who really knew everybody. . . . This is what they need to be. They need to do better.’’
Davis said that most teams have developed strong relationships with residents and local merchants, but reports like Andelman’s trouble him.
“This is definitely a work in progress,’’ he said. “These concepts are so different from how police used to do their jobs. It requires a constant amount of training. If we don’t do that, the teams will revert to the old way of doing things.’’
The teams work in East Boston, Downtown Crossing, Jamaica Plain, the South End, Roxbury, Mattapan, and Dorchester. The areas were picked because they were consistently plagued by violence or crime.
For example, the Bowdoin-Geneva area typically has among the highest number of shootings in the city; 51 in 2008, 24 in 2009, and 24 in 2010, according to police figures.
The analysis of the Safe Street teams program showed that robberies fell 19 percent and aggravated assaults, which includes shootings, fell 15 percent in the areas targeted by the teams.
The inability of the teams to reduce the number of homicides and sexual assaults is probably linked to the nature of the crimes, which are often between people who know each other, and primarily in the case of rapes, indoors, Davis said.
“It’s a very difficult conversation about reducing the numbers in those two categories simply by police presence,’’ he said.
Officials should consider whether the teams could expand their reach and intervene in the gang conflicts that often lead to homicides, Braga said.
The study, which cost about $125,000 and was funded through a grant by the US Department of Justice, was done objectively and will be reviewed by other academics, said Braga, who described himself as an unpaid advisor to Davis.
“We have valid statistical evidence that’s defensible, that indicates this strategy is positive,’’ Davis said.