Serious crime in Cambridge dipped slightly last year to its lowest level in nearly 50 years, and police are giving the credit to increased reliance on statistical data.
Police Commissioner Robert C. Haas said crime data analysis has helped police pinpoint trends in crime and predict future incidents.
“In the old days, we used to randomly patrol neighborhoods,’’ Haas said. “Now, it’s very much directed. It’s very methodical. . . . It’s more about preventing future victimization.’’
Yet, while the overall number of serious crimes in the city was down by 1 percent from the year before - and 5 percent lower than the 5-year average, according to the department’s data - some categories of crime saw an increase, though the department said those spikes were not statistically significant.
In explaining the declines announced yesterday, Lieutenant Daniel Wagner, who heads the Cambridge Police Crime Analysis Unit, said his unit is able to identify upswings of a particular crime in a specific area or at a certain time.
For example, officers may see a spike in reported pickpocket incidents. By using data analysis, they could determine that most of the crimes occur between 2 p.m. and 4 p.m. in a particular square.
Using that information, officials can decide to assign more patrol officers to head off those crimes.
“I’m optimistic that we can continue to reduce crime,’’ Wagner said. “I think that we’re at somewhat of a tipping point in terms of developing more advanced, comprehensive ways to use predictive analytics for crime mapping.’’
One category that saw an increase in crime is homicides. There were no murders in Cambridge in 2010, but there were five in 2011.
Haas said those killings were mostly the result of domestic disputes that could not have been anticipated by police.
Commercial robberies also rose by 55 percent, from 22 in 2010 to 34 robberies in 2011.
People interviewed near the Central Square MBTA stop had mixed views on the state of the city’s safety.
Angel Vasquez, 41, was surprised to hear that crime is down. He has been working in Central Square since 2001, and from his perspective, things have gotten much worse in the past decade.
While he’s seen an increased police presence in the neighborhood, he continues to see people selling drugs outside his window. After dark, he always escorts a secretary from his office downstairs because he worries that violent people may be hiding in the stairwell.
“It’s a recipe for destruction,’’ Vasquez said. “You gotta kind of watch yourself.’’
But Ellie Laramee, 29, said she is not concerned. She lives in Somerville, but she’s been working in Cambridge for years.
“I love Cambridge. I never feel unsafe here, walking or biking,’’ Laramee said. “I’d never hesitate to walk out to my car at night.’’
As Laura Pacheco, 41, and Alison Goldberg, 37, pushed their children in strollers down Massachusetts Avenue, they said they seldom worried about the neighborhood.
“At least for us, it’s been a pretty safe place to live,’’ Goldberg said. “I mean, like anywhere else, there are problems, but I’m never worried about it.’’
“In any community, you have to be on your toes,’’ Pacheco added. “But that’s city life.’’
Martine Powers can be reached at email@example.com.