Racial Profiling: Real or Illusion?

Let's think about cause-effect logic here:

A report by a civil liberties group has found that Los Angeles police officers are more likely to stop and search black and Hispanic residents than they are whites, even though whites are more often found carrying guns and contraband.

Even after researchers controlled for demographics and neighborhood crime rates, they found significantly higher stop rates for black and Latino residents. For every 10,000 residents, blacks were nearly three times more likely to be stopped than white and other "non-minority" residents, facing 3,400 more stops. Hispanics were stopped on 350 more occasions.
...
Tim Sands, president of the Los Angeles Police Protective League union, strongly disputed the report's findings and pointed out that the department mirrors the racial demographics of Los Angeles, with more Hispanic officers than white officers.

"Dr. Ayres is trying to manipulate existing data to prove what 9,700 individual officers are thinking when they make traffic stops - which is an exercise that might work on a spreadsheet at Yale, but doesn't work on the streets of Los Angeles," Sands said.

AP

We are comparing effects, not causes.

Imagine if we looked at traffic stops and found that one-legged people were arrested more.

We would assume bias. Good logic, right? Not really, since we don't know what other factors are in play.

One-legged people could commit more crime.

One-legged people could be harder to describe than two-legged people, leading to many more stops of the wrong one-legged people.

One-legged people could live in impoverished, more criminal neighborhoods where more traffic stops are needed to pre-empt criminal behavior.

The "logic" used by this study is suspect.