The Sean Bell shooting and probability

http://wmbriggs.com/blog/2008/05/08/the-sean-bell-shooting-and-probability/ ^ | W M Briggs

[mattstat]

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The Sean Bell shooting and probability

Yesterday, there were several protests in New York City. The participants were “outraged” over the recent acquittal of two black cops and one Lebanese cop who shot and killed Sean Bell, who was black.

Much was made over the fact that the three cops shot at Bell’s car 50 times. This number was touted repeatedly by some as evidence that the cops had used excessive force.

Let’s look at this from the probabilistic viewpoint. It turns out that when a cop fires his weapon at a person, he only hits his target about 30% of the time. Anybody who has ever fired a weapon before, especially in an altercation, will know that this is a pretty good rate, but of course not good enough to guarantee that just one shot will be enough to stop a target.

So about how many times must a cop fire so that he is at least 99.9% sure of hitting his target?

[Smokin' Joe]

Keep shooting until the threat is no longer a threat. Shot placement helps, for sure.

[tickmeister]

I believe this is called the “spray and pray” theory of gunfighting. It almost always loses to the other method, which consists of doing the long and hard work required to learn to hit what you are shooting at under stress. The good news is that the bad guys never do that work.

[B4Ranch]

Neither do most good guys.