It was a scenario many have imagined: Retiring to a lonely beach in Mexico after a few minutes of a heart-pounding crime — like Bonnie and Clyde riding into the sunset with a good stash of money attained through a handful of bank heists.

A group of scientists armed with a "normally confidential data set" decided to test the financial realities of robbing banks (pdf) and they found that it simply doesn't pay. Well, that's speaking figuratively. In reality, the statisticians report it does pay — just "not very much."

Here is their conclusion:

"The return on an average bank robbery is, frankly, rubbish. It is not unimaginable wealth. It is a very modest £12 706.60 [$19,734] per person per raid. Indeed, it is so low that it is not worth the banks' while to spend as little as £4500 [6,989] per cashier position at every branch on rising screens to deter them. A single bank raid, even a successful one, is not going to keep our would-be robber in a life of luxury.

"It is not going to keep him long in a life of any kind. Given that the average UK wage for those in full-time employment is around £26 000, it will give him a modest lifestyle for no more than 6 months. If he decides to make a career of it, and robs two banks a year to make a sub-average income, his chances of eventually getting caught will increase: at 0.8 probability per raid, after three raids or a year and a half his odds of remaining at large are 0.8×0.8×0.8=0.512; after four raids he is more likely than not to be inside. As a profitable occupation, bank robbery leaves a lot to be desired."

The Wall Street Journal reports the same is true in the United States, where 1,081 robberies occurred. The average "loot" in the U.S., according to the FBI? $5,531.

The authors of the study note that bank robbers already got the hint.

"Bank robberies and attempted bank robberies have been decreasing, in both the USA and the UK; in the UK, robberies from security vans are on the increase. Security vans offer more attractive pickings," the authors report.

The study appears in the June 21 issue of Significance,a statistics journal published on behalf of the Royal Statistical Society and the American Statistical Association.

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