As airport security lines get longer, travelers continue to ask: are all the baggage screenings, shoe removals, and pat-downs worth the extra time and hassle?
TSA is moving towards increasingly risk-based security approaches, so decisionmakers need to consider not just the threat posed by our adversaries, but the cost effectiveness of security efforts to reduce the expected consequences from those threats.
RAND researchers recently examined how we can better assess the costs and benefits of aviation security interventions, despite uncertainties about the terrorist threat and security system performance, in order to help policymakers decide on potential changes to the system.
Trusted traveler programs (such as the current TSA PreCheck program) are an attractive strategy for making security more efficient and reducing security burdens on some travelers. Such programs can be used to improve overall security and the more people who are willing to join the program, the greater the saved resources that can be used to improve security screening for other travelers.
However, some benefits of security measures, such as how they deter attackers or shape the choices they make, are more difficult to measure and therefore often left out of assessments of whether security measures have enough value to justify what they cost. For example, the Federal Air Marshal Service would have to be stopping or deterring terrorist attacks on far more flights than air marshals are actually on in order to justify its cost. But the difficulty of assessing the number of attacks deterred makes the net value of costs or savings very difficult to measure.
The aviation system is currently protected by a layered security system, where several lines of defense must be breached for an attack to be successful. However, multiple layers don't always add up as one might expect--in some cases, they will reinforce another, but in some cases they will interfere with another. Better understanding of how layers "add up" is critical for getting the best value from security, since new layers on top of old are costly and can make the aviation system more difficult for passengers and other users.
RAND researchers also examine how historical data on aviation security can inform future security planning; examine ways to address uncertainty about the costs of security measures by attempting to quantify them; and discuss the models of terrorism risk currently in use by DHS.
Please don't hesitate to contact me at (703) 413-1100, ext. 5423 or Laura_Selway@rand.org if you want additional information from RAND, would like to speak to a researcher, or have any questions.
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