The chance of being killed by terrorists is the same as tossing a coin 20 times and getting heads each time, Cambridge professor David Spiegelhalter, says in his Guardian blog.
Spiegelhalter is professor of the public understanding of risk at Cambridge University.
“Assessing reasonable odds is important for insurers who need to set premiums,” he says.
“Up to 2001 they were sceptical about large losses from terrorism but $35bn in claims from the Twin Towers has made them a little more cautious, and now ‘catastrophe modellers’ use expert judgment to assess the chances of attacks, and then complex mathematical models to predict the casualties and damage for everything from aircraft impact to smallpox and dirty bombs.”
So why does it feel inappropriate to compare the risks of terrorism with the chance of, say, a fatal car accident on a 200 mile journey (which is another 1-in-a-million chance)? One idea is that terrorism presses many of the buttons that psychologists have identified as features of "dread" risks: we feel out-of-control, it affects the vulnerable, and we have seen media coverage of the consequences resulting in a strong sense of "outrage".
Cass Sunstein, a senior advisor to Obama, claims that people display "probability neglect" when confronted with vivid images of terrorism, so that "when their emotions are intensely engaged, people's attention is focused on the bad outcome itself, and they are inattentive to the fact that it is unlikely to occur". So the "true" risks are ignored: it's been shown that people are, rather illogically, willing to pay more for insurance against terrorism than insurance against all risks, just because the use of the word conjures up dread.
