An unknown man cruised into the corporation's private parking lot, flashing the security guard his driver's license instead of a company ID. He entered corporate headquarters and advanced through the marble and glass lobby. The officer at the sign-in podium never even looked up. From there, it was a quick elevator ride to the executive suite where he displayed to the secretary a "personal and confidential" letter for the CEO. "Sure, take it in yourself," she said. "The boss is in there now."
The man delivered his message with a flourish, tossing it onto the CEO's walnut desk. The boss looked up in horror. "Gotcha!" it read. The perpetrator was the security contractor's district manager, out to prove that a security breach could happen easily.
Many opinions were voiced in the aftermath of the stunt. Some said the problem was the low wage paid the security officers. Others thought it was the lax work ethic of the employees. Still others focused on a lack of proper training. The eventual outcome - and the one that the district manager wanted - was a 50 percent increase in the contractor's permanent working hours. But was this the best approach to better security?
No. A better approach is human factors psychology, the application of behavioral science to workplace performance issues. Human factors methods, especially signal detection theory (SDT), can be used to diagnose performance problems, reduce threats, improve security officer morale, and save time and money.
Hit or miss. A major element of a security officer's job is to detect rare events. Once in a while, a driver like the district manager tries to enter a private lot with a false ID. Similarly, an occasional visitor will fail to sign in at the lobby security podium. The security officer's duty is to decide whether or not these actions indicate that danger is present.
When faced with a potential "rare target," the security officer's decision results in one of four outcomes, three of which have consequences. The officer can take action and intercept a genuine threat - a hit, as it is called; the officer can take action in the absence of a threat, raising a false alarm; the officer can take no action and experience no negative outcome - a correct rejection; or the officer can take no action and allow a crime or other security breach to occur.
A hit could stop a thief or an ex-employee bent on revenge. For security officers and their supervisors, a hit might mean a bonus. A miss can lead to real trouble - an injured employee, stolen money or merchandise, or theft of company secrets. Too many misses and a security contractor might be terminated. The third outcome with a consequence - a false alarm - will be tolerated to a point, but too many false alarms gives an officer a detrimental hair-trigger reputation.
Signal detection theory. Signal detection theory is a systematic, data-based approach to human vigilance that can help maximize the likelihood of a hit, whether the target is a false ID or a weapon in a suitcase, while minimizing false alarms. Applied wherever rare events must be caught, SDT has improved the detection of defects by inspectors in automotive, glass, and aircraft manufacturing operations. SDT has also been used to increase a physician's chance of detecting hard-to-find breast tumors.
Two factors fundamentally affect the detection of rare targets, regardless of whether the target is a tumor in human tissue, a bubble in a glass windshield, or a mugger in the bushes. First is the detectability of the target, or the ratio of the strength of the stimulus to the "background noise." Second is the bias, or expectancy, that a target will actually appear.
Detectability. With regard to metal detection, for example, such weapons as a .44 magnum revolver would have a very high hit rate and a low false alarm rate. On the other hand, a difficult target would be a weapon such as the largely plastic Glock 17, containing less than half the steel in a . …