Professor Mark G. Stewart is Professor of Civil Engineering and Director of the Centre for Infrastructure Performance and Reliability at The University of Newcastle, Australia. He is co-author of several books and has written more than 300 technical papers and reports. He has more than 25 years of experience in probabilistic risk and vulnerability assessment of infrastructure and security systems that are subject to man-made and natural hazards. Since 2004, Mark has received extensive Australian Research Council (ARC) support to develop probabilistic risk-modelling techniques for infrastructure subject to military and terrorist explosive blasts and cost-benefit assessments of counter-terrorism protective measures for critical infrastructure. In 2011, he received a five-year Australian Professorial Fellowship from the ARC to continue and to extend that work.
 

The presentation will review key findings of a new book Terror, Security, and Money: Balancing the Risks, Benefits, and Costs of Homeland Security (Oxford University Press, September  2011). The book uses risk-based decision theory to determine acceptability of risk which is crucial to prioritise counter-terrorism measures.  Key points are:

• The cumulative increase in expenditures on US domestic homeland security over the decade since 9/11 exceeds one trillion dollars. Australia has increased its homeland security expenditures to over $8 billion in total which is less than a quarter per capita of what the U.S. spends on homeland security. How much of this expenditure is necessary? and how much has been effective?
• The presentation will describe a cost-benefit analysis that considers threat likelihood, cost of security measures, risk reduction and expected losses to compare the costs and benefits of security measures to decide which security measures are cost-effective, and those which are not.
• We find that enhanced U.S. expenditures have been excessive. To be deemed cost-effective, the security measures would have to deter, prevent, foil, or protect each year against 167 otherwise successful attacks that each inflicted some $1 billion in damage (nearly one every two days). This is the destruction of what might have happened had the Times-Square bomber of 2010 been successful.
• We also find that the protection of standard office-type buildings or bridges would be cost-effective only if the likelihood of a sizable terrorist attack on the building is a thousand times greater than it is at present. On the other hand, hardening cockpit doors on airliners is cost-effective, though the provision for air marshals is not.