Terrorist risk is 20 coin tosses

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.”