Security Analysis of TSA PreCheck
Interesting research: Mark G. Stewart and John Mueller, “Risk-based passenger screening: risk and economic assessment of TSA PreCheck increased security at reduced cost?”
Executive Summary: The Transportation Security Administration’s PreCheck program is risk-based screening that allows passengers assessed as low risk to be directed to expedited, or PreCheck, screening. We begin by modelling the overall system of aviation security by considering all layers of security designed to deter or disrupt a terrorist plot to down an airliner with a passenger-borne bomb. Our analysis suggests that these measures reduce the risk of such an attack by at least 98%. Assuming that the accuracy of Secure Flight may be less than 100% when identifying low and high risk passengers, we then assess the effect of enhanced and expedited (or regular and PreCheck) screening on deterrence and disruption rates. We also evaluate programs that randomly redirect passengers from the PreCheck to the regular lines (random exclusion) and ones that redirect some passengers from regular to PreCheck lines (managed inclusion). We find that, if 50% of passengers are cleared for PreCheck, the additional risk reduction (benefit) due to PreCheck is 0.021% for attacks by lone wolves, and 0.056% for ones by terrorist organisations. If 75% of passengers rather than 50% go through PreCheck, these numbers are 0.017% and 0.044%, still providing a benefit in risk reduction. Under most realistic combinations of parameter values PreCheck actually increases risk reduction, perhaps up to 1%, while under the worst assumptions, it lowers risk reduction only by some 0.1%. Extensive sensitivity analyses suggests that, overall, PreCheck is most likely to have an increase in overall benefit.
The report also finds that adding random exclusion and managed inclusion to the PreCheck program has little effect on the risk reducing capability of PreCheck one way or the other. For example, if 10% of non-PreCheck passengers are randomly sent to the PreCheck line, the program still is delivers a benefit in risk reduction, and provides an additional savings for TSA of $11 million per year by reducing screening costs—while at the same time improving security outcomes.
There are also other co-benefits, and these are very substantial. Reducing checkpoint queuing times improves in the passenger experience, which would lead to higher airline revenues, can exceed several billion dollars per year. TSA PreCheck thus seems likely to bring considerable efficiencies to the screening process and great benefits to passengers, airports, and airlines while actually enhancing security a bit.