Spinning Good News Into Bad

Via Radley, I find a USA Today article about trends in drunk-driving accidents. As Radley notes, the number of drunk-driving-related deaths fell nationwide from 2005 to 2006, and it also fell in 28 states. Yet the headline reads, “Drunken driving deaths up in 22 states.” Talk about seeing the glass half-empty.

Even more statistical deception lies within the article. While the number of traffic fatalities involving drivers with BAC of 0.08 or above dropped (from 13,582 in 2005 to 13,470 in 2006), the number of fatalities involving drivers with any alcohol at all their systems rose slightly (from 17,590 in 2005 to 17,602 in 2006). Guess which statistic the Secretary of Transportation decided to focus on?

"The number of people who died on the nation's roads actually fell last year," U.S. Transportation Secretary Mary Peters said at a news conference in this Washington suburb. "However the trend did not extend to alcohol-related crashes."

Naturally, these statistics are being used to promote an expanded campaign against drunk driving, with the slogan, “Drunk Driving. Over The limit. Under Arrest.” But wait a minute – the number of fatalities involving drivers over the legal limit went down!

Even if we focus on fatalities involving drivers with any alcohol at all in their systems, we should still adjust for population growth. By my calculations, the number of such fatalities per 100,000 fell slightly, from 5.93 in 2005 to 5.88 in 2006.

And, as Radley observes, all statistics of this nature are based on the underlying assumption that alcohol was the cause of every accident in which one of the drivers had alcohol in his system – whether or not that driver was deemed at fault.