Tuesday, August 20, 2013

No evidence for Stop-and-frisk reducing crime

There's a long piece in the Washington Post (Wonkblog) today about claims that stop-and-risk reduce crime. I'm now becoming obsessed not with police brutality, per se, but with the discourse of police explanations. 
“No question about it, violent crime will go up,” New York police commissioner Ray Kelly declared on Meet the Press on Sunday, when asked if a recent ruling striking down the city’s “stop and frisk” policy would cost lives. “What we’re doing — and what we’re trying to do — is save lives,” he added on This Week.
Actually, there are some questions about it. The research is clear: Stop and frisk is applied racially unevenly. But there’s precious little evidence that it has worked to reduce crime. And then there’s the question of whether it could actually be undermining effective policing by alienating the very communities it’s meant to help.
What I like about the piece is the way the author then moves through social science research, the claims it makes, the claims it can make, and the limitations of available data. He concludes:
Ultimately, Weisburd argues that this is the kind of question that you need a true experiment to resolve. “Let’s say they did a randomized experiment, with 500 control blocks and 500 treatment blocks, where you measure the number of minorities who live on each block,” Weisburd says. “They would have answers to the questions being asked.” Until then, Kelly is operating on the basis of precious little evidence, and in the face of serious drawbacks to the approach he’s chosen.
Also this lead poisoning thing - that violent crime is down because we are not being poisoned by lead - seems to have legs.