Lessons from LA crime data issues


We’ve made some updates to our Los Angeles crime data, and the story behind these updates is a good example of the sort of behind-the-scenes work we do at EveryBlock to improve our data sets and advocate open government data in general.

Last week, the Los Angeles Times reported that the Los Angeles Police Department’s online mapping system was missing nearly 40 percent of crimes, compared to data the LAPD released separately to the Times. It also reported that the LAPD’s public-facing crime site is separate from its internal system (CompStat) — which implies at least two separate databases are being maintained for Los Angeles crime data.

Given that this online mapping system is our source for EveryBlock’s Los Angeles crime section, we were pretty interested in finding out whether the LAPD would address this discrepancy and maybe even combine the two systems to avoid the problem entirely.

One part of the problem was addressed quickly. Shortly after the Times story was published, the LAPD added thousands of crime reports to its mapping system — reports from earlier in 2009 that had previously been omitted. After speaking with the Times and the police, we at EveryBlock reimported the entirety of crime data available on the LAPD’s crime site, which contains reports going back to the beginning of this year. (EveryBlock users in Los Angeles might have noticed this change in daily alerts today, which might have contained crime reports that were several months old.)

We thank the Times for its reporting on this, as it improved the amount of information available on the city’s public crime-mapping Web site as well as on EveryBlock. The crime-mapping system is our only source for the data, as we note in our LA crime section.

A couple of items are worth noting in this episode. In a follow-up story, LAPD officials indicated that they were reviewing their data policies, including their agreement with their crime-mapping vendor as well as their decision to share a separate set of data with the Times.

We have contacted the department and asked that EveryBlock be considered in any new data-sharing solution. We also shared some insights with the LAPD on the provision of crime data, based on the years of work we’ve done with police departments and other agencies across the country.

At EveryBlock, we seek to have good working relationships with all of the dozens of agencies we deal with in the 15 cities we cover. In the course of our work, we’ve seen many approaches to the publication of data, especially crime. We suggested that the LAPD take a look at the example of the San Francisco Police Department.

As we note in our San Francisco police calls section, the SFPD publishes a raw data feed, exported from their system. Because it’s a single source of data directly from the department’s system, it easier to maintain and eliminates the errors that arise from multiple databases.

The Times article noted that Los Angeles Police Chief William J. Bratton “was worried, he said, that he’d have to give it to anyone ‘in his underwear in a basement somewhere.'” By adopting a feed like this — and directing all third-party services to use it — we could all get the most complete information, at the same time and from the same source. And that’s good for everyone, regardless of where they spend their time or what they happen to be wearing.

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