Economic Analysis of Bank Robberies

From: Schneier on Security

Yes, it’s clever:

The basic problem is the average haul from a bank job: for the three-year period, it was only £20,330.50 (~$31,613). And it gets worse, as the average robbery involved 1.6 thieves. So the authors conclude, “The return on an average bank robbery is, frankly, rubbish. It is not unimaginable wealth. It is a very modest £12,706.60 per person per raid.”

“Given that the average UK wage for those in full-time employment is around £26,000, it will give him a modest life-style for no more than 6 months,” the authors note. If a robber keeps hitting banks at a rate sufficient to maintain that modest lifestyle, by a year and a half into their career, odds are better than not they’ll have been caught. “As a profitable occupation, bank robbery leaves a lot to be desired.”

Worse still, the success of a robbery was a bit like winning the lottery, as the standard deviation on the £20,330.50 was £53,510.20. That means some robbers did far better than average, but it also means that fully a third of robberies failed entirely.

(If, at this point, you’re thinking that the UK is just a poor location for the bank robbery industry, think again, as the authors use FBI figures to determine that the average heist in the States only nets $4,330.00.)

There are ways to increase your chance of getting a larger haul. “Every extra member of the gang raises the expected value of the robbery proceeds by £9,033.20, on average and other things being equal,” the authors note. Brandishing some sort of firearm adds another £10 300.50, “again on average and other things being equal.”

We all kind of knew this — that’s why most of us aren’t bank robbers. The interesting question, at least to me, is why anyone is a bank robber. Why do people do things that, by any rational economic analysis, are irrational?

The answer is that people are terrible at figuring this sort of stuff out. They’re terrible at estimating the probability that any of their endeavors will succeed, and they’re terrible at estimating what their reward will be if they do succeed. There is a lot of research supporting this, but the most recent — and entertaining — thing on the topic I’ve seen recently is this TED talk by Daniel Gilbert.

Note bonus discussion terrorism at the very end.