A scientific risk analysis for terrorism?

While fingering through a stack of used and outdated magazines at the gym yesterday, I came across a Newsweek article written by Fareed Zakaria, which posits that the American political, military, and psychological response to 9/11 has proven excessive. The subtitle of his article, available online here, is indeed rather candid: "It's clear we overreacted to 9/11." At this point, I imagine his argument strikes most readers as commonsensical, perhaps even banal. Yet we continue to pour resources into a multiplicity of wars, occupations, and covert "counter-terrorism" operations. Likely, the general level of hysteria required to justify this profligacy persists because there remain both: (1) enough people genuinely frightened of a broadly conceived "terrorist threat", and (2) enough people who retain an interest in its perpetuation. It follows then that if both of these groups could be eliminated, a change in policy might be more likely. For this project, I have a useful starting point: applying scientifically-tested risk-assessment techniques to the putative threat of terrorist attack.

In fact, Zakaria's article reminded me of a study I read in Foreign Affairs last Spring, which employed just such risk-assessment techniques in an analysis of the threat posed by terrorism. The article is available here.

To illustrate the thrust, consider the following quotes:

"Over the last several decades, academics, policymakers, and regulators worldwide have developed risk-assessment techniques to evaluate hazards to human life, such as pesticide use, pollution, and nuclear power plants. In the process, they have reached a substantial consensus about which risks are acceptable and which are unacceptable..."

"...Typically, risks considered unacceptable are those found likely to kill more than 1 in 10,000 or 1 in 100,000 per year..."

"...There is a general agreement about risk, then, in the established regulatory practices of several developed countries: risks are deemed unacceptable if the annual fatality risk is higher than 1 in 10,000 or perhaps higher than 1 in 100,000 and acceptable if the figure is lower than 1 in 1 million or 1 in 2 million. Between these two ranges is an area in which risk might be considered "tolerable...""


Now, lest this scientific language strike you as intolerably detached, keep in mind this kind of analysis' importance to formulating public policy in almost every regard: e.g. speed limits, medical regulations, workplace safety requirements, etc. Thus, it seems entirely appropriate to apply such an approach in the similarly safety-oriented endeavor of ensuring our collective defense from terrorist attack. But what do we find when looking at the risk presented by terrorism in a deliberately unemotional, empirical, and quantitative manner? This:



To quote the authors: "annual terrorism fatality risks, particularly for areas outside of war zones, are less than one in one million and therefore generally lie within the range regulators deem safe or acceptable, requiring no further regulations, particularly those likely to be expensive. They are similar to the risks of using home appliances (200 deaths per year in the United States) or of commercial aviation (103 deaths per year). Compared with dying at the hands of a terrorist, Americans are twice as likely to perish in a natural disaster and nearly a thousand times more likely to be killed in some type of accident. The same general conclusion holds when the full damage inflicted by terrorists -- not only the loss of life but direct and indirect economic costs -- is aggregated. As a hazard, terrorism, at least outside of war zones, does not inflict enough damage to justify substantially increasing expenditures to deal with it."

Perhaps its true that a picture (or a table) is a more eloquent communicator than any string of well positioned words. Still, I feel like articulating the question -- "should we frantically ramp up our counter-home-appliance measures?" -- in its stark preposterousness is worthwhile.

The full article is not to be missed.