Are We Safe Enough? Measuring and Assessing Aviation Security brings into focus our thoughts on aviation and airport counterterrorism security measures, thoughts that have been fermenting for nearly a decade now. Over this period we have published 10 peer-reviewed journal articles on the subject and have spoken at numerous conferences, workshops, seminars, and public meetings. However, our two previous books—Terror, Security, and Money: Balancing the Risks, Benefits, and Costs of Homeland Security (Oxford University Press, 2011) and Chasing Ghosts: The Policing of Terrorism (Oxford University Press, 2016)—each devoted only one chapter to aviation or airport security. Yet these chapters elicited more questions and interest from the media than the others when the books were launched in Washington, DC. There is much more to be said on this topic.

Approximately $50 billion is spent annually world-wide in the quest to deter or disrupt terrorist attacks to aviation. These are significant expenditures that have rarely been subject to systematic cost-benefit or risk analysis. This lack of scrutiny leads to risk-averse and costly counterterrorism policies. Some aviation security measures may not even be needed.

We find that often the question being asked on this issue is not the right one, or worse, that questions are not being asked at all and “safety at any price” is hardwired into the DNA of decision makers.

For example, in 2017, one former administrator of the Transportation Security Administration, speaking on the condition of anonymity in order to be able to speak candidly, told the Washington Post, “It’s hard to quantify it, because all of this is about risk. This is about security, so the more security elements we have in place, the more secure the traveling public in railroad stations and airports are going to be” ( Halsey, 2017). That is, what this top official considered important was to keep throwing “security elements” at the problem without bothering to investigate a key, even elemental, question: does the added element improve security enough to justify its cost?

Our analyses show how this issue can be quantified, and they often reveal that some security measures reduce risk only microscopically and/or at enormous cost. Why these measures have not been subject to more careful scrutiny by government agencies or Congress is, quite simply, baffling. This condition provides much of the motivation for this book.

The book will explain how standard risk analytic and cost-benefit analysis can be applied to aviation security in systematic and easy-to-understand steps. It seeks to evaluate—to put into sensible context—the risks associated with air travel, the risk appetite of airlines and regulators, and the notion of acceptable risk. It does so by describing the effectiveness, risk reduction, and cost of each layer of aviation security, from policing and intelligence to checkpoint passenger screening to arming pilots on the flight deck. A systems model measures not only the overall risk reduction these layers provide, but, more importantly, the additional risk reduction each layer contributes. For example, the air marshal program in the United States costs over $1 billion annually, but changes overall risk reduction only marginally from 99.1% to 99.3%. The questions then become: is this a cost-effective security measure, and are there less expensive ways to achieve the same level of safety?

This book seeks to answer such questions in a scientifically rigorous and fully transparent manner. The calculations are generally easy to follow and can be done on a hand calculator or on Excel. The robustness of the findings is explored through sensitivity analyses.

The key feature is the quantification of risks, costs, and benefits. This book explains how to track and measure changes in risk reduction in today’s security environment and in the one that prevailed before 9/11. Much of this has worldwide applicability, and the book goes some way to challenging preconceived notions while providing critical guidance for arriving at evidence-based policy.

Our thinking about, and understanding of, aviation security issues has benefitted from our discussions and interactions with colleagues and the general public over many years, and we have noticed that the response has been overwhelmingly positive to our line of thinking. To our surprise, most accept that decision makers are overly, even irresponsibly, risk averse; that the political imperative that drives this aversion to any risk is absurd; and that there is a need for a different and more balanced approach to aviation security. People often seem to be able to respond to adult talk about terrorism in a sensible way, and overreaction does not seem to be a political requirement. We hope that this book contributes further to this conversation.

About the Authors

Mark G. Stewart is Professor of Civil Engineering and Director of the Centre for Infrastructure Performance and Reliability at The University of Newcastle in Australia. He is co-author of Probabilistic Risk Assessment of Engineering Systems (Chapman & Hall, 1997, and Japanese edition in 2003), and has published more than 400 technical papers and reports. He has 30 years of experience in probabilistic risk and vulnerability assessment of infrastructure and security systems that are subject to man-made and natural hazards. Professor Stewart has received extensive Australian Research Council support, including an Australian Professorial Fellowship, to develop probabilistic risk-modeling techniques for infrastructure subject to military and terrorist explosive blasts, and cost-benefit assessments of aviation security, policing, and counter-terrorism protective measures for critical infrastructure.

John Mueller is Woody Hayes Senior Research Scientist at the Mershon Center for International Security Studies and Professor of Political Science at Ohio State University, as well as a Senior Fellow at the Cato Institute in Washington, DC. He is the author of over a dozen books, several of which have won prizes. Among the most recent of these: War and Ideas (2011) Atomic Obsession: Nuclear Alarmism from Hiroshima to Al-Qaeda (2010), Overblown (2006), and The Remnants of War (2004). He has also edited the web book, Terrorism Since 9/11: The American Cases (2017). Earlier books include Capitalism, Democracy, and Ralph’s Pretty Good Grocery, Retreat from Doomsday, Astaire Dancing, and War, Presidents and Public Opinion. He has published hundreds of articles in scholarly journals and general magazines and newspapers, is a member of the American Academy of Arts and Sciences, and has been a John Simon Guggenheim Fellow.

The above article is the Preface to the author’s new book Are We Safe Enough? Measuring and Assessing Aviation Security is available online via ScienceDirect. If you would prefer to order a print or e-copy, visit the Elsevier store here. Apply discount code STC317 at checkout and receive 30% off the list price and free global shipping.