The Italian Job, or what are you planning next week?

Each year there are more bank robberies in Italy (approximately 3,000) than in the rest of Europe combined, with a 10 percent chance of victimization on average.

…The average robbery lasts 4.27 minutes and leads to a haul of approximately 16,000 euros. Given that more than half of all bank robberies involve two or more perpetrators, the average haul per criminal is approximately equal to 8,700 euros.

…only about 40 percent of all bank robbers disguise themselves when robbing a bank.

Those are some perplexing facts from the scientific study 'Optimizing Criminal Behavior and the Disutility of Prison' by Giovanni Mastrobuoni and David A. Rivers.

Here is the 'Abstract' should you be interested in optimizing your criminal behavior.

We use rich microdata on bank robberies to estimate individual-level disutilities of imprisonment. The identification rests on the money versus apprehension trade-off that robbers face inside the bank when deciding whether to leave or collect money for an additional minute. The distribution of the disutility of prison is not degenerate, generating heterogeneity in behavior. Our results show that unobserved heterogeneity in ability is important for explaining outcomes in terms of haul and arrest. Furthermore, higher ability robbers are found to have larger disutilities, suggesting that increased sentence lengths might effectively target these more harmful criminals.

How should you go about, what should you avoid?

Not surprisingly, traveling to the robbery by foot and targeting a bank with a security guard are both consistent with lower ability offenders. There is also evidence that higher ability robbers target banks in the late afternoon around closing time.

You don't want to be a low-ability offender, right? You might now be interested in your yearly earnings potential.

The median haul per robber is € 5,300. Data collected from the Milan police (Mastrobuoni, 2017), in which serial bank robbers are tracked over time, show that the median number of days between bank robberies is 10. Given that the overall arrest rate is 6.6 percent, the expected number of robberies in a year is approximately 14. For a robber with the median frequency of robberies and the median haul, the anticipated yearly haul is close to € 75,000, which is in line with the annual value of compensating variation that we find.

Ok, so far so good. However, there is also the other side of the equation you would need to put into perspective and that is

6.2 Deterrence

Given our estimates of disutility, we can ask the question, by how much would policy makers need to increase the disutility of prison in order to push the optimal robbery duration to zero. Using our estimates of the expected haul and hazard of police arrival, we calculate this for each observation by computing the value of the disutility D such that t∗ = 0 in equation (4). Letting this value be denoted as Dt=0, and letting Dt=t∗ be the estimated value corresponding to the observed duration, we have that the percentage increase in disutility needed for robbers with an observed t∗ > 0 to drive the duration to 0 is given by logDt=0 −logDt=t∗. We then compute the associated percentage increase in sentence length needed to drive t∗ to 0 for di erent values of the discount factor. (Note that for a discount factor of 1, the necessary percentage increase in disutility and sentence length are equivalent.)

Finally, if you are still interested in this career path some things should be considered. Like weapons, masks, yes or no, and not to be discounted whether you consider yourself to be a 'higher ability offender' and are able to cope with a higher disutility.

The estimates in Tables 3 and 4 identify the robbery characteristics that are most strongly associated with differences in hauls and apprehension rates. For hauls, the use of a weapon and/or a mask leads to larger hauls, as does targeting banks with fewer security devices and no guards. Regarding arrests, working in groups, wearing a mask, and targeting banks with no security guard and few employees are associated with a decreased likelihood of getting caught. Our estimates suggest that judges and lawmakers may want to target these robbery characteristics (in terms of sentence enhancements) in order to reduce the harm created by bank robberies. There is evidence that this is already occurring in Italy and elsewhere, for example in US state and federal legislation, particularly for crimes involving firearms, groups of offenders, and masks. One caveat to this is that our estimates reflect both the causal effects of these characteristics as well as the indirect effects of the ability of those individuals who select them. Robbers (particularly high ability ones) may respond to an increase in the penalty for certain robber characteristics by simply selecting different ones, as opposed to not committing a robbery, partially mitigating the deterrent effect. Ideally, one would like to target the high ability offenders directly, since these robbers cause the most damage (more money lost and more repeat offenses). This is challenging though because ability is unobserved. One additional benefit of our estimates is that they suggest that a broader policy instrument could have a similarly targeted impact. We find that higher ability offenders, in addition to having improved outcomes, have a larger disutility of prison, possibly due to a higher opportunity cost of imprisonment. As a result, they are likely to be more sensitive to increases in sentence length. By increasing sentences overall, an important implication is that high ability offenders are indirectly and disproportionately targeted.45

Not surprisingly, unobserved robberies lead "to systematically better outcomes". You might want to keep that in mind before we come to the

7 Conclusions

Using unique and detailed data on almost 5,000 Italian bank robberies, we estimate how the haul and likelihood of arrest vary with characteristics of each robbery, including the unobserved ability of the robbers. Using information on the observed robbery duration we estimate individual-specific values of the compensating variation of imprisonment. We find evidence of large differences across offenders. Our estimates provide strong evidence that unobserved ability of robbers leads to systematically better outcomes for these offenders: larger hauls and lower arrest probabilities. We also find that higher ability offenders have a larger disutility of prison, potentially due to the opportunity cost of being incarcerated.

So the only thing you would need now is a Mini Cooper and remember, "You were only supposed to blow the bloody doors off !"

H/T MR