Wednesday, January 23, 2013

Body Scanner: Who says looks don’t count?

By Prof. Alan (Avi) Kirschenbaum*

The recent decision of the TSA to replace one type of body scanner with another is, at first glance, a remarkable shift in policy for the agency that is the final arbitrator of all matters dealing with airport security. Even more surprising, this decision was brought about by the pressures of non-airport security stakeholders (the Electronic Privacy Information Center), and related to privacy issues rather than security.

Source: TSA blog
This shift in policy is, of course, a bit simplistic as the installation of alternative body scanners remains. The goal is to detect as fast as possible those persons who carry items deemed a threat to security. My emphasis on “as fast as possible” is the reason for body scanners as airport management is extremely sensitive to increasing “through-put,” that magical word that is directly linked to bottom line profits or losses. It is a technological fix that fits into the assembly line design of airports as a people-processing factory. But the technology does have its limits. And people aren’t always compliant.

This was brought home in an analysis, during the BEMOSA project, of the role that passengers play at screening check points. For conventional screening (and it seems for full body scanners as well), screening detection and threat avoidance is guided by rule compliance. The technology is very sophisticated, but we found that there was a problem with employees bending, breaking or ignoring the rules, and even more problematic was passenger behavior. Passengers argued and negotiated with the security employees! What we discovered was that security checking is a complex social process and not the simplistic picture of automated filtering by technology.

The critical time factor of the passenger negotiating over a prohibited item not only put the proverbial monkey wrench into the spokes of the technology, but was, in fact, the key to the flow affecting passenger “through-put.” Shaving off 2-5 seconds per passenger by an advanced algorithm paled in comparison to the time-consuming social process of negotiating whether to open a bag, go through the metal detector, refusal to give up an expensive bottle of whisky or even take off shoes!

So the TSA policy change is really no change at all as it still continues (with an internal logic of justification) to seek the design of a better mouse trap. But to do so there still remains the missing link – employees and passengers. Perhaps the king will realize he is naked only when the evidence proves it to be the case.


*The writer is the initiator and coordinator of BEMOSA (Behavioral Modeling of Security in Airports).

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