How Data Took Down NYC's Stop and Frisk

When statistics and the testimony of young black men come together, justice may be possible after all.

A stop-and-frisk protester holds up a sign. (Allison Joyce/Getty Images)

(The Root) -- On Monday, federal Judge Shira A. Scheindlin ruled that the New York City Police Department's stop-and-frisk practices were unconstitutional, but to thousands of the city's black and Latino men, that wasn't news. The real headline for many in New York's black and brown communities was how attorneys convinced a federal judge that the city had violated the Constitution by engaging in years of racial profiling. 

The answer to that riddle can be found largely in one place: data crunched by Jeffrey Fagan, a Columbia University professor whose research has now made long-standing complaints of millions of black and Latino men an objective reality.

Scheindlin relied heavily on a pair of painstaking researched studies by Fagan, who is a criminologist. One study addressed the plaintiffs' concerns that the police practice violated the Fourth Amendment, which protects against unreasonable searches; the other that stop and frisk violated the 14th Amendment's protections of equal protection under the law for all Americans.

"The city adopted a policy of indirect racial profiling by targeting racially defined groups for stops based on local crime suspect data," Scheindlin wrote, to the chagrin of city officials. It was Fagan's two studies that largely led her to this conclusion. 

For the claim against the Fourth Amendment, plaintiffs argued, using Fagan's research, that the police weren't able to justify enough of their stops. "The data was straightforward and ... we believed that police were following a script in the basis for their stops, like 'furtive movement' or 'high-crime area,' " Fagan told The Root in an interview. "Police said they were stopping people based on whether they matched a suspect's description, and looking at the data that only accounted for roughly 13 percent of stops.

"They're obviously stopping people based on thin signs of suspicion, like a 'suspicious bulge' in their pants or 'evasive action,' " he added. "And these are hardly suspicious behaviors, unless the police spent a long time observing the suspects."

Regarding the 14th Amendment's demand for equal protection under the law, police testified that they were simply stopping people in high-crime areas. Fagan debunked this by developing a statistical model that compared the number of stops in each enforcement area, along with the race of the people stopped. He also found that blacks and Hispanics, once they had been stopped, were more likely to be subjected to the use of force.

"We tested that, saying, 'Knowing the crime rate, we should be able to predict the stop rate in the neighborhood, and no other factor should enter that equation,' " Fagan explained. "Turns out, even after you account for the relationship between crime and stops, there was still a relationship between the racial component of the population and the stop rate. This means it wasn't only about crime, but crime and race. That's the basis of the discrimination claim."

Of course, Mayor Michael Bloomberg and New York Police Commissioner Ray Kelly vehemently disagreed with the judge's conclusions. They even presented their own experts, who tried to poke holes in Fagan's analysis.

"This is a very dangerous decision made by a judge who I think does not understand how policing works," Bloomberg said, according to the Daily News. He also said that he hoped the city could continue using the practice through the appeal process because "I wouldn't want to be responsible for a lot of people dying."