The researchers expected that the number of crimes committed per person would fit a statistical distribution shaped like a bell if the criminal acts were being committed by random people in the selection: only a tiny fraction of boys would commit no crimes or lots of crimes, and most boys would fall into the average slot of committing a medium number of criminal acts.
Instead they found that that crime rates fell into a mathematical pattern called a power law, in which large deviations from average behaviour are more common. In both studies, most of the boys committed no crimes at all. In the Pittsburgh study, quite a few boys reported over 1,000 criminal acts during the study period, while the average number was just 90.
Physicists often find power-law statistics in systems with many interacting parts. This suggests that the young boys in the study are not responding randomly and independently to criminal opportunities that come their way. Instead they are probably influencing one another, presumably through strong peer pressure.
When the researchers subtracted results from the boys who had committed no crimes, they found a slightly different, better fit to a power law for the remaining subjects. This seems to indicate that people who commit no crimes are living in a different world from those who do – mathematically speaking.
The bottom line?
The best way to combat casual crime is not to search for persistent offenders but to deter people from committing their first crime…”Crime is never going to go away,” says Ormerod. But, he says, the best way to reduce it is to stem the flow of individuals into the criminal population.