Evaluating the Effectiveness of Security Countermeasures
Amidst all the emotional rhetoric about security, it's nice to see something well-reasoned. This New York Times op-ed by Nicholas Kristof looks at security as a trade-off, and makes a distinction between security countermeasures that reduce the threat and those that simply shift it.
The op ed starts with countermeasures against car theft.
Sold for $695, the LoJack is a radio transmitter that is hidden on a vehicle and then activated if the car is stolen. The transmitter then silently summons the police - and it is ruining the economics of auto theft....
The thief's challenge is that it's impossible to determine which vehicle has a LoJack (there's no decal). So stealing any car becomes significantly more risky, and one academic study found that the introduction of LoJack in Boston reduced car theft there by 50 percent.
Two Yale professors, Barry Nalebuff and Ian Ayres, note that this means that the LoJack benefits everyone, not only those who install the system. Professor Ayres and another scholar, Steven Levitt, found that every $1 invested in LoJack saves other car owners $10.
Professors Nalebuff and Ayres note that other antitheft devices, such as the Club, a polelike device that locks the steering wheel, help protect that car, but only at the expense of the next vehicle.
"The Club doesn't reduce crime," Mr. Nalebuff says. "It just shifts it to the next person."
This model could be applied to home burglar alarms:
Conventional home alarms are accompanied by warning signs and don't reduce crime but simply shift the risk to the next house. What if we encouraged hidden silent alarms to change the economics of burglary?
Granted, most people don't want hidden alarms that entice a burglar to stay until the police show up. But suppose communities adjusted the fees they charge for alarm systems - say, $2,000 a year for an audible alarm, but no charge for a hidden LoJack-style silent alarm.
Then many people would choose the silent alarms, more burglars would get caught, and many of the criminally inclined would choose a new line of work....
I wrote about this in Beyond Fear:
A burglar who sees evidence of an alarm system is more likely to go rob the house next door. As far as the local police station is concerned, this doesn't mitigate the risk at all. But for the homeowner, it mitigates the risk just fine.
The difference is the perspective of the defender.
Problems with perspectives show up in counterterrorism defenses all the time. Also from Beyond Fear:
It's important not to lose sight of the forest for the trees. Countermeasures often focus on preventing particular terrorist acts against specific targets, but the scope of the assets that need to be protected encompasses all potential targets, and they all must be considered together. A terrorist's real target is morale, and he really doesn't care about one physical target versus another. We want to prevent terrorist acts everywhere, so countermeasures that simply move the threat around are of limited value. If, for example, we spend a lot of money defending our shopping malls, and bombings subsequently occur in crowded sports stadiums or movie theaters, we haven't really received any value from our countermeasures.
I like seeing thinking like this in the media, and wish there were more of it.
Posted on July 1, 2005 at 12:19 PM • 50 Comments