Monday, February 14, 2005

Better with numbers

Daniel Okrent, the New York Times' public editor, shares letters from readers who share his annoyance with misleading numbers in the news. (Okrent wrote a column on the matter three weeks ago.) One writes:
You say, "Numbers without context, especially large ones with many zeros trailing behind, are about as intelligible as vowels without consonants." ...

A five-pound mouse is one heck of a mouse. A five-pound elephant is, equally, an amazing elephant. Yet the number means exactly the opposite in each case.

Small numbers can be equally deceptive. A sales tax goes from 3 percent to 4 percent; a 1 percent rise or a 33 percent rise? (Only the incumbent knows.)

Numbers without context -- and fictional ones concocted for selfish ends -- saturate the media. I am dismayed The Times does not have a numeracy department.
Shouldn't that department be the copy desk? (And note the mistake about the change of 1 percentage point vs. 1 percent. However, it is possible the writer knows the difference but is implying that politicians don't. Given that this is one of the most pervasive math problems I see in stories, though, it's a good example of how that mistake can skew a story.)

Another reader complains that using the general "many" instead of precise numbers is "loaded, slanted, lazy, hazy." But context is everything, as this reader pointed out:
The Times's front-page blizzard article on Jan. 23 told readers that "all three airports remained open, but 175 flights were canceled at Kennedy, 120 more were canceled at Newark, and 200 were canceled at La Guardia, where delays ran up to two hours." That left me wondering how the remainder of flights -- however many there were -- could possibly be taking off in the blinding snow.

The Daily News put my concerns at ease: "By midafternoon, nearly all passenger flights had been canceled at Kennedy, La Guardia and Newark airports." Less precision can be far more meaningful.
Okrent made a couple of mistakes himself when he wrote his column on numbers a few weeks ago, and he corrects the record:
Only hubris could have led me to write three weeks ago about the misuse of numbers, for it was inevitable that I would misuse some myself. A couple of readers pointed out that the Treasury Department no longer issues the 30-year bond I took as a standard against which New York City's potential investment in a stadium could be measured.

And several called me to account on my computation of the return on Harvard's endowment. The $82 million allotted by Harvard for undergraduate financial aid is equal to what its endowment produces in seven and a half days, not six days; and the $2 million set aside last year for students from low-income households is equal to the endowment's appreciation in 4 hours 23 minutes -- not 3 hours 36 minutes. I think.
So who checked his math? One thing's for sure: Readers did.

(Link via Charles Apple at the Visual Editors board.)


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