If you do physical security seriously, this 63 page study of burglars who got caught is worth reading. The general thrust is not news to anyone — most burglars use forced entry, only one in 8 pick locks or use previously acquired keys.
However, the details are fascinating.
Alarms provide the strongest possible deterrent, with only 8% saying they always try to disable an alarm and 60% going somewhere else if they saw an alarm at all. Of burglars that planned their crimes, the number of alarm-avoiders was even higher.
Still, a full 20% of burglars cut telephone or alarm wires in advance of their burglary. And something to keep in mind when you’re working late and the only one in the building, the presence of people on the property was only enough to deter 60% of the crooks!
Fortunately, most burglars aren’t looking for trouble.
Female burglars tended to go a’burgling with their partner or spouse on “spur of the moment” afternoon home burglaries to support prescription drug habits, while male burglars favored planned nighttime commercial burglaries for the money with their friends.
Nevertheless, the study suffers one flaw. Though most of the surveyed crooks were highly experienced, the authors acknowledge they couldn’t survey burglars who’d never been caught. An excellent example of belling the cat, as applied to scientific research: “If possible, future research should investigate possible differences among burglars who have and have not apprehended.”
“Similar to previous findings (Rengert & Wasilchick, 2000; Wright & Decker, 1994), most burglars in this sample did not plan their crimes in advance. […]
Regardless of whether the crimes were planned in advance, the majority of these burglars
indicated they would consider a number of factors before committing a burglary. The largest
proportion of respondents considered cameras/surveillance equipment, followed by alarms,
people inside the structure, dogs, and cars in the driveway. They said they tended to avoid
targets that had people inside, a police officer nearby, noise inside, alarms, or if they saw
neighbors. Notably, both the planners and those who did not plan were likely to seek alternative targets if they detected the presence of an alarm.
When asked specifically about alarms, the vast majority of burglars said they never
attempted to disable alarms, while only 8% indicated they always tried to disable an alarm.
Once the decision has been made to burglarize a structure, these burglars reported most
often entering the premises through windows or doors (either already open or forcing them
open). Only a few respondents reported picking locks or other entry methods. The most
common tools carried by these burglars were screwdrivers, crow bars, and hammers.
Still, we cannot be sure whether these findings can be generalized to the total
population of burglars in these and other states. Specifically, it is not known if the patterns
established from this sample would apply to burglars who have not been caught and/or
incarcerated for their crimes. For example, active or former burglars who have not been
apprehended for their crimes may have different motivations, spend more time planning their
crimes, consider different factors when choosing targets, or use different techniques during crime
commission as compared to those who have been arrested and convicted for burglary. If
possible, future research should investigate possible differences among burglars who have and have not apprehended.”