Every so often, a journalist or politician proclaims that Americans are more likely to die from slipping in the bathtub (or from car accidents, or lightning strikes) than terrorist attacks—a point most recently made by Nicholas Kristof in the pages of the New York Times. Justin Fox dissects this particular bit of statistical sophistry:
First [of all], terrorism is designed to . . . sow terror. As [Janan] Ganesh writes, “most people can intuit the difference between domestic misfortune and political violence. The latter is an assault on the system: the rules and institutions that distinguish society from the state of nature. Bathroom deaths could multiply by 50 without a threat to civil order. The incidence of terror could not.”
Second, . . . ladders, stairs, and bathtubs are undeniably useful. Terrorists, less so.
Finally, comparing the incidence of terrorism with that of common accidents is an incompetent and irresponsible use of statistics. Household accidents are lots and lots of small, unrelated events. As a result, while individual accidents can’t be predicted, the overall risk is easy to quantify and is pretty stable from year to year.
Terrorism is different. There are small incidents, but there are also huge ones in which hundreds or thousands of people die. It’s [what statisticians call] a “fat-tailed distribution,” in which outliers are really important. It also isn’t stable: five or ten or even 50 years of data isn’t necessarily enough to allow one to predict with confidence what’s going to happen next year.
Read more on Bloomberg: https://www.bloomberg.com/view/articles/2017-02-14/stop-telling-me-how-dangerous-my-bathtub-is