A Study on Burglar Alarm Effectiveness for Suburban Homes Using Data Gathered from
Greenwich, Conn.
*Study partially underwritten by the Alarm Industry Research and Educational Foundation (AIREF);
Source: Dr. Simon Hakim, Temple University
“Security precautions that address the criteria of deterrence, preventions, and detection
significantly reduce a property’s chance of becoming a burglary victim. Previous studies have
shown that effective deterring precautions are a car in the driveway, exterior and interior lights,
watch dogs, and active neighborhood watch programs. Effective prevention measures are locking
doors, with deadbolt locks being preferred. The only detection measure is a burglar alarm.”
There are four basic types of precautions which must be provided to significantly reduce the
chance of burglary:
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Deterring Measures: These are security measures which are likely to lower the chance
of a break-in when the burglar cruises the neighborhood in search of a target. Burglars
search for homes that appear to be unoccupied. Thus, deterring measures suggest that
somebody is at home. For example, a car in the driveway, motion sensitive exterior
lights, interior lights, and radios and TVs on timers, all give the impression that someone
is in the home.
Preventive Measures: These are security measures which make the actual break-in more
difficult and/or time consuming. Burglars spend no more than 60 seconds breaking into a
home. Measures which rise this time may cause burglars to change their mind. Some
examples include deadbolt locks, bars on windows, and pins in sash windows.
Detection Measures: These are measures which detect the presence of an intruder on the
premises and send a message out. Only a burglar alarm serves that purpose.
Managerial Measures: In nature, these measures are in the deterrence category. They
are not physical precaution measures like the three previous categories but are associated
with the deterring category in their objective, which is to produce the impression that
somebody is home. They include stopping newspaper and mail delivery, notifying police
when you will be away, and having neighbors watch your home.
Our previous surveys revealed that effective security requires maintaining deterring, preventive
and detecting precaution measures. A burglar alarm is always part of the required package.
Surveys also show that people who own alarms hold significantly more precautions than nonalarmed residents. Alarmed homes which were burglarized relied mainly on the alarm but did not
maintain a sufficient number of other precautions. Effective security measures include an alarm
or more of the other precautions which address the deterring and preventive categories.
Alarms are considered complementary to other security precautions; that is, no other precaution
has the deterring power of the alarm. The alarm reduces the chance of burglary 66.2 percent
when three or more precautions are taken by the homeowner.
Another benefit of an alarm concerns the value of the property stolen. Average loss from
burglary is $3,266 when there is an alarm and $5,343 when there is no alarm. When an alarm is
present, the burglar is limited in the time he can spend on the premises.
“Regardless of the distance from either type of major thoroughfare, alarms are effective. In both
cases, alarm effectiveness increases with distance from thoroughfares, demonstrating the
burglar’s desire to stay close to an escape route. Figure 3.1.2 demonstrates that unalarmed homes
located within a quarter mile of any major thoroughfare are 1.81 times more likely to be burgled
than their alarmed counterparts. That factor increases to 2.82 as the distance from thoroughfares
increases. Unalarmed homes within a quarter mile of an exit from one of the four major routes
are 1.85 times more likely to be burgled than a similarly situated alarmed home. That factor
increases to 2.69 as the distance from the exit increases. On back roads, the risk of burglary is
5.89 times higher for unalarmed homes than for alarmed homes. Clearly, alarms are effective in
decreasing the risk of burglary with respect to locational risk factors.”
While the probability of burglary is 13.8 percent for alarmed properties on busy residential
streets, it is a 1.37 times higher, or 18.9 percent, for similarly located unalarmed properties.
Single family homes are most often targeted for burglary. Their risk is 35 percent greater than
that of the entire population. They are more attractive than other types of properties for several
reasons. First, single family homes portray wealth, especially as compared to townhouses and
twins. They also provide the burglar with more cover than do other properties, so as they tend to
be located further from neighboring properties that the other types. Single family homes also
provide the burglar with more alternatives for entry to the property. Despite the attractiveness of
single family homes, alarms are effective in deterring intruders. An alarmed single family home
is more than 60 percent less likely to be burgled than a similar home without an alarm.
Unalarmed homes valued at more than $600,000 have as much as 5.5 times the burglary risk of
alarmed houses with the same value.
Alarm owners recognize these benefits. Our Pennsylvania study showed that 94 percent of alarm
owners were satisfied with their decision to buy an alarm. This study shows that 93 percent of
owners are satisfied with their security company.