Friday, January 19, 2007

Murder Statistics Don't Tell The Whole Story

WSJ's The Numbers Guy looks at two ways to analyze crime statistics in a city. Murder rates mislead. The idea that interested me most was how the health care system affects crime rates. In cities where good trauma centers exist (like Houston), murder is less likely. Assault would then be the charge, but the city is still violent--using guns to kill.

Think of a comparison between two hospitals' death rates (a topic I wrote about last year). If Hospital A has a higher proportion of patients suffering from life-threatening diseases, it wouldn't be fair to compare its death rate to Hospital B, which tends to treat patients with milder complaints. Prof. Friedmann's team believes that certain cities (Atlanta, Detroit) have higher underlying risk of murder than others (Denver, San Francisco).
Hmmm.... So the crime rates might be the same? You're just more likely to live in Denver and San Fran? Well, it's interesting, anyway.

This kind of begs the question: Do people change their behavior because of perceived risk? So, people perceive San Francisco as safer, so they engage in riskier behavior like going to dangerous neighborhoods to eat. I don't know. In New Orleans, I feel unsafe no matter where I am. Ditto Miami. Those cities just reek of menace. Detroit has whole areas that I wouldn't be caught in, either. Yet I feel safer in Manhattan and Chicago and Houston. Go figure. Is it perception or reality?

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