Police officers walk or drive “beats” around neighborhoods for two reasons. First, they look for crimes-in-progress (or using their training, evidence that a crime is imminent). Second, and more importantly, they hope to be seen, to deter future crime from taking place.
So imagine a heavily patrolled area. A crime happens, the police on patrol catch the criminal, the criminal is found guilty and goes to prison.
Is that event evidence of a successful system or a failing system?
On the one hand, the police patrols clearly are not deterring ALL crime; obviously we know that because this one criminal got caught. Some people might look at this and say “well, there is clearly no way we are catching all criminals; the fact that we caught one means that crimes are being committed, and therefore the police patrols need to be stepped up.”
On the other hand, the police patrol worked. A crime was committed, the police caught the criminal, and he went to jail. That’s what the police are supposed to do; catch criminals. In fact, we could look at this incident as a positive, because it means that the patrols are capable of catching some criminals.
Personally, I think both are reasonable issues. Of course, if a truly rational individual were interested in solving that question, s/he would first need to answer some of the underlying assumptions made by each assertion. Are other crimes being committed that are falling through the cracks? What kinds of evidence should we look for? Can we measure the effectiveness of the police patrols as deterrence? Does the fact of a conviction here actually increase the deterrent effect for future criminals, or is it only evidence that this one criminal got particularly sloppy or unlucky? Those are all questions that would need to be asked before we can make a rational judgement about whether this crime is evidence for the success or failure of the police patrols.
But we don’t live in a rational world. We live in a world where people like to jump to very reasonable sounding conclusions, with little or no actual evidence.
We live in a world where, on the one hand, sports writers across the country take it as a sign that baseball’s steroid policies are absolutely failing because two all-stars were caught juicing up in the randomized drug testing that all Major Leaguers must submit to. They juiced up, they got caught, and that by itself is evidence of a failed testing system?
Of course, we also live in a world in which prosecutors and police chiefs put out impressive sounding statistics about the number of arrests made, to justify to voters that they stay in their jobs. But again, isn’t an arrest evidence of a failure somewhere else?
Intelligent, informed members of American society walk around today assuming that baseball is dirty, because they keep catching people, and assuming that football is clean, because they haven’t caught a high-profile player using steroids in a couple years. Of course any one of those people will admit that it might just be because football isn’t looking as hard–but even that thought won’t stop them from making the assumption.
Which all gets back to one simple truth: being an intelligent, informed, and unbiased citizen isn’t just hard. It’s impossible.