October 07, 2005
The math of terrorist threats
Posted by
Mark Kleiman
Let's imagine that a successful subway attack would kill or injure 100 people, and that there's one chance in 50 of an attack on any given day when heightened warnings are in place. With an average weekday ridership of 4.5 million, that puts the probability of being hurt or killed at about 1 in 2 million, or, in technical statistical language, approximately fuhgettabadit.
The individually rational response to all such threats is identical with the socially optimal response: go about your business and let the cops worry about catching the bad guys. The mass media, by falsely dramatizing all such warnings, make our civilization more vulnerable to terrorist threat than it needs to be.
