Cop stop study data veiled in darkness

"We note that based on interviews and talking with [police] officers, these data cards contribute to low morale and there's a certain frivolity to them."

San Diego State University researcher Josh Chanin, on the team that has been combing through 259,000 "stop cards" filled out by San Diego police, told a city-council committee Wednesday (October 26) that the cards are unreliable.

Researchers explained how they used a method known as "veil of darkness" that assumes cops can't see drivers to identify their race or ethnicity after dark and therefore aren't able to racially profile drivers between the hours of 5:30 and 9 p.m. during the times of year when the sun goes down early.

The method has been used in seven other studies, Chanin said. But the method didn't jibe with everyone: a man spoke about getting pulled over after a cop drove by him and did a U-turn — after dark.

The full study was supposed to be released, but the mayor's office pulled it back and selected parts that could be released. (The researchers' contract with the city allows for a 30-day review before it goes public, according to city-council staff.)

"White drivers were stopped less than what the demographic profile of the city may predict," Chanin said, noting that Asians were similarly treated. "Black drivers are 20 percent more likely to be stopped during the day," he said, noting the raw numbers suggest that police pull over young black men at a rate 45 percent higher than young white men.

The numbers changed from 2014 to 2015, with disparities seen in 2014 disappearing the next year, Chanin said. In the five police divisions north of the I-8, traffic stops of black people showed a disparity of 15 percent; south of the I-8, in the four police divisions, white drivers were 20 percent more likely to be pulled over than black drivers and 30 percent more likely than Hispanic drivers.

Blacks and Hispanics were more likely to be searched — cars and bodies, but whites were more likely to be carrying guns, drugs, and other contraband. White drivers were given citations more often than black drivers, and the arrest rates were about the same. But the data wasn't great.

"There were 60,000 to 70,000 traffic stops that were not recorded by officers," Chanin said.

With data collected in a method that the researchers said should be discontinued ("veil of darkness") and limits on what the mayor's office would allow the public to see, Norma Chavez-Peterson of the American Civil Liberties Union of San Diego and Imperial Counties expressed dissatisfaction.

"The information provided by the mayor's office leaves a lot of questions," said Chavez-Peterson. "The information and analysis were not presented in a way that's easy to understand — we hope the final report will not require a sociologist or statistician to understand."

But it was clear from what was available that people of color were more likely to be stopped, more likely to be searched, and less likely to have guns, drugs, or other illegal stuff, Chavez-Peterson said.

Councilwoman Myrtle Cole, who mentioned her time as a police officer, was blunt: "Are you saying there's 67,000 cards out there?" she asked. "In order for a community to trust, we need all the data....

"When I first came on in 2013, I was hearing about racial profiling. I was hoping it was going to get better. My community is telling me it is not getting better."