How it WorksBy Elizabeth Bennett | Posted 2006-02-07 Email Print
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Serious crime is down in the nation's second-largest city. A big reason for the drop: LAPD's use of an analytics system to tailor its enforcement strategies.
Godown says he then learned that some of the department's critical information systems, which had been in use for years or even decades, were deficient and outdated. The Consolidated Crime and Arrest Database (CCAD), into which all crime information is first entered, was more than 20 years old and not accurately reporting all criminal activity, he recalls.
For instance, a report might have shown 40 robberies in a particular area, even while a handful of those incidents had already been classified as "unfounded." It took the Compstat unit a year and a half—while the Compstat program was up and running—to make sure that all the information collected and analyzed was "true and correct," according to Godown.
The Compstat technology staff had to reprogram the CCAD, an IBM DB2 mainframe maintained in downtown L.A. by the municipality's Information Technology Agency. Now, the data in the mainframe replicates every five to 10 minutes to an Oracle database, so there is no chance of inadvertent data errors.
Godown's staff had to nail down the flow of information, from the crime on the street to the bound book of statistics prepared for every Compstat meeting. "It was important for me as the officer in charge that no one could come back and blame my system," he says.
The process goes like this: When a crime such as a robbery is committed, the officer who responds to the call fills out a report by hand. The report includes the type of crime, the class of crime (homicide, larceny, etc.), a description of the stolen goods, the location or address from which they were taken, and a physical description of the suspect, if there is one.
The commander on duty reviews the report for thoroughness and accuracy. He makes sure addresses are correct and that the elements of the crime have been carefully and legibly explained.
The report is given to employees working in the division headquarters, and they enter the data into the Consolidated Crime and Arrest Database. Civilian staffers assign a three-digit code for type of crime and a four-digit code for modus operandi. For example, attempted rape is 122; "suspect aimed a gun" is 0302. There are eight separate codes for the shape of a suspect's nose, including crooked, hooked, small and flat.
Crime analysts in the various police divisions and the Compstat unit download text files containing the consolidated crime information to the Crime Mapping Database (CMDB), a Microsoft Access database that can produce reports summarizing each area's crime for any time frame, maps with the location of some or all crimes committed, and breakdowns of individual crime types. For example, an analyst could query the system for all assaults in the Valley's Foothill Area for the week of Jan. 15 and then plot the results.
The CMDB is integrated with mapping software from Troy, N.Y.-based software developer MapInfo. Maps can be tailored to display crime types in a geographic region. A simple map might display auto thefts for a particular time period. With a few clicks, analysts can direct the application to show all parks and malls in the area, the time of day of each theft, and nearby burglaries and robberies. With that snapshot, a more nuanced and useful picture could emerge. These maps are projected onto three 5-by-8-foot screens at every Compstat meeting, different ones for each division.
Also generated in the Crime Mapping Database are "counter" reports that list each type of weapon used in violent crimes, the weapon code, how many of each weapon type were used in the period, the ethnicity and age of suspects and victims, and the suspects' modus operandi.
The counter is useful for spotting trends. It can show, for example, that Toyota cars made prior to the mid-1990s are the most commonly stolen vehicles in Los Angeles. Armed with that information, the department has issued public service announcements, and area commanders launched security initiatives such as putting fliers on the windshields of older Toyotas to alert owners of the risk. In 2005, thefts of all Toyota models decreased by 12%, from 7,507 to 6,591.
At the December Compstat session, assistant chief Gascon, who leads the meetings, suggests that Valley Bureau captains take their car-theft fight one step further. He says captains should work with local Toyota dealerships to promote the installation of kill switches in aging Toyotas. For Gascon, solving this problem isn't an isolated activity: "If we could lower auto theft in the Valley, we could lower crime by 1% or 2% citywide." With Bratton's new goal of reducing overall crime by 8% in 2006, clamping down on Toyota thefts takes on a new urgency.