Another Statistical Study Indicates LAPD Racial Profiling

Last Thursday's Los Angeles Times printed an op-ed by Yale Law Professor Ian Ayres that presents the details of a statistical analysis of more than 700,000 interactions between LAPD officers and pedestrians and motorists between June 2003 and June 2004. The results of the study were revealed at a press conference by the ACLU of Southern California on Monday.

We found persistent and statistically significant racial disparities in policing that raise grave concerns that African Americans and Latinos in Los Angeles are, as we put it in the report, "over-stopped, over-frisked, over-searched and over-arrested." After controlling for violent crime rates and property crime rates in specific neighborhoods, as well as a host of other variables, we found the following:

For every 10,000 residents, about 3,400 more black people are stopped than whites, and 360 more Latinos are stopped than whites. Stopped blacks are 127% more likely to be frisked -- and stopped Latinos are 43% more likely to be frisked -- than stopped whites.

Stopped blacks are 76% more likely to be searched, and stopped Latinos are 16% more likely to be searched than stopped whites.

Stopped blacks are 29% more likely to be arrested, and stopped Latinos are 32% more likely to be arrested than stopped whites.

Now consider this: Although stopped blacks were 127% more likely to be frisked than stopped whites, they were 42.3% less likely to be found with a weapon after they were frisked, 25% less likely to be found with drugs and 33% less likely to be found with other contraband. We found similar patterns for Latinos.

Not only did we find that African Americans and Latinos were subjected to more stops, frisks, searches and arrests than whites, we also found that these additional police actions aren't because of the fact that people of color live in higher-crime areas or because they more often carry drugs or weapons, or any other legitimate reason that we can discern from the rich set of data we examined.

The LAPD's response was typically weak. Police Chief Bill Bratton complained that the study used data that was more than four years old, but the LAPD itself has not made the latest data of its traffic stops available. Bratton also complained that the study hadn't considered the effect of the race of the officers involved. But Professor Ayres had a reply:

When testing for unjustified racial disparities in who is stopped by the police in cars and on the street, it's inappropriate to control for the race of either of the officers. The likelihood of being stopped, frisked or arrested shouldn't turn on whether a black, Latino or white officer was involved.

As an ancillary test -- after we'd calculated the general disparities -- we did look at the officers involved, and we found that the racial disparities in the likelihood of arrest were substantially lower when at least one of the stopping officers was the same race as the suspect.

For example, we found that the black arrest disparity was 9 percentage points lower when at least one of the stopping officers was black. Bratton should be troubled that there is less disparity when the officer is the same race as the person stopped, as that result adds credibility to the idea that the disparities in different-race interactions may be because of racial bias.

The Los Angeles Times editorial board noticed Bratton's smackdown and came to his rescue on Saturday, gingerly.

That being said, the LAPD does have a history of profiling, but it is in statistical denial of that fact. Not one of the 320 profiling complaints filed last year was validated by the department, nor were any of those filed in the five previous years. Blacks and Latinos are stopped and searched more frequently than whites, and few would deny the probability that some of those stops are unwarranted. After all, this is a relationship on the mend, not one that has fully healed.

The real problem seems to be that for all its efforts, the LAPD does not yet know how to detect and quantify disparate treatment. Ian Ayres, the professor who prepared the ACLU report, says he can help, and the department should take him up on his offer. The truth surely lies somewhere between the spotless image claimed by the department and the sullied one implied by the report.

Ball's in your court, Bill.