Column: How the LAPD has achieved better policing through data

Every Wednesday morning, supervisors and officers of the Los Angeles Police Department gather in a windowless room on the first floor of the department’s headquarters. There, they analyze crime statistics and get grilled about their strategies for improvement by the department’s command staff. This is Compstat, the metric-driven system that has helped the LAPD achieve historic crime reductions and inspired Mayor Eric Garcetti’s efforts to create meaningful metrics for other city departments.

On the morning I attended a Compstat analysis, the LAPD’s beam shone on the Mission Division in the San Fernando Valley. Capt. Todd Chamberlain was at the podium. His principal inquisitor was Chief of Staff Stephen “Rick” Jacobs.

Jacobs began with homicides. He was pleased to see they were down for the year in the division (there had been five killings to this point last year, compared with four this year), but he wanted to hear the details of one recent homicide. Chamberlain was ready with the explanation. It was, he said, a family fight: A disturbed young man clashed with his mother and stabbed her.

Dispensing quickly with the homicide — not the kind that lends itself to prevention by policing — Jacobs moved to more worrisome indicators. Aggravated assaults, though down for the year, had jumped in March, and the number of shots fired had doubled from four to eight in early April.

Again, Chamberlain was prepared with an answer. The leadership of the Blythe Street Gang was fragmenting, he explained, leading to a power struggle between various factions. They were fighting it out with gunfire — mostly shots into cars or into the air. His explanation illustrated a point Los Angeles police are grappling with: As crime has dropped, a higher percentage of what remains is committed by gangs, making strategies for combating gang violence more important than ever.

Asked how police were responding to the violence caused by Blythe Street, Chamberlain explained that officers had begun stepping up patrols in the contested areas, a traditional police response. But that wasn’t all. In addition, officers were working with the office of Councilman Tony Cardenas to encourage a truce, and meeting with church leaders and parishioners to counsel young people away from violence. Officers were also enforcing an injunction that limits the activities of known gang members in the area.

Those answers, reflecting the kind of comprehensive approach required by community policing, seemed to please Jacobs.

One of the theories that undergirds the Compstat system is James Q. Wilson’s notion, articulated in his landmark 1982 article “Broken Windows,” that small crimes and neighborhood decay, if not stopped, tend to lead to more serious offenses. With that in mind, Jacobs wanted to know about a recent uptick in shoplifting and petty thefts in the Mission Division, some of which had escalated into assaults when security guards or store owners confronted thieves.

The chief culprit, officers said, was a large Wal-Mart operating in Panorama City. Police have tried to persuade the company to hire uniformed security guards to deter shoplifting, but the company has not agreed to do so. That, in Chamberlain’s view, was a problem, since Wal-Mart has become the largest single source of reported thefts in the Mission Division. (Last week, a Wal-Mart spokeswoman told me the company was continuing to speak with the LAPD and was eager to come up with solutions that might reduce calls to police.)

Police are continuing to lean on the company, however, and may have some new leverage. Wal-Mart is hoping to open a store nearby, and the company is seeking a conditional-use permit to sell liquor. The Police Department, officials said, might oppose that permit unless the company demonstrates a willingness to work cooperatively on neighborhood crime.

The analysis went on to other topics — traffic stops and accidents; use-of-force incidents by officers, with special emphasis on the types of force and the records of the officers using it; reclassification of serious crimes to less serious ones, always an important area to monitor to protect against cooking the books (about 1.5% of all crimes are reclassified after further investigation, so the number is small but still crucial to watch).

After an hour or so, Jacobs complimented Chamberlain on his command of his area, and left him with a few items to consider for their next session.

And that, in essence, is what makes Compstat work. For all the focus on data and mapping, its real genius is in the conversations it requires as police officers and supervisors answer to their bosses, in front of colleagues and the public. That is real accountability. It has helped make Los Angeles safer, and it’s why Garcetti wants more of it.

jim.newton@latimes.com

Twitter: @newton_jim