Thursday, December 25, 2008

Numbers in the newsroom

Two good reminders that we too often get carried away with numbers without providing context, and especially, proper context.

  • "On the Media" led last week's show with an interview with Michael Blastland, co-author of "The Numbers Game," and a book I intend to get on my desk as soon as possible. Blastland and host Bob Garfield throw back and forth on the absurdity of some of the numbers being used ($700 billion bailout, $50 billion fraud) without giving people some sense of their context. Blastland suggests that perhaps that $700 billion isn't so bad at all when compared with the economy's total broken down per person.
  • In response to a Poynter E-media Tidbits post about this week's dam break and spill of coal fly ash across part of the the western Tennessee landscape, one reader challenged the rather common comparison of saying things like it was equivalent to almost 800 (average) Olympic-sized swimming pools. I think the commenter, Alex Dering, has a good point: First, unless there is a standard depth for an Olympic pool, "average" is rather suspect. Second, most people see Olympic pools not as volume but as surface area. I think that's very important - when we use comparisons, we need to use them as people recognize them, and sometimes people do not "see" all dimensions. (Example: You have a 200-foot-deep well whose opening is 6 feet across. To most people, that's perceived as a 6-foot-wide hole (with the accompanying area dimensions generally understood) and not a 1,200 7,200-cubic-foot cylinder (though I am using the word "cylinder" here, you can see from my numbers -- and thanks to Pete for outpointing the mistype -- that I conceived of it more square. I suppose I could have used "column" instead. If, indeed, you take it as a round hole, the volume's about 5,600 cubic feet, as Pete points out.) When we run into huge numbers, we risk losing all sense of proportion anyhow because there is little on Earth to compare with which we have direct knowledge. (And, as the critic points out, saying something will stretch x times in relation to distance to the moon basically still just produces "gee, that's a large number.")
I've found that time is perhaps the one thing that people identify with that can still reasonably handle large numbers in a way that gives an idea of what is at stake. Some handy conversion factors:
  • 86,400 seconds in a day
  • 604,800 seconds in a seven-day week
  • 31,536,000 seconds in a (365-day) year.
So if the government spent a dollar per second, it would take almost 22,200 years to spend all $700 billion. (As Blastland also said, per-person comparisons can work will in some cases, too, but only when the amounts bear some reasonable relationship to the average person's economic condition.)

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At 12/30/08, 1:04 AM, Blogger Pete said...

A 6-foot-wide well at 200 feet deep would not yield a 1,200-cubic-foot well, by virtue of the fact that volume is surface area times depth. And the area of a circle is pi times radius squared, yielding ~28.27 square feet of surface, times the 200-foot depth, or ~5,655 cubic feet.

At 1/1/09, 4:02 AM, Blogger Doug Fisher said...

Good point. Actually that was a mistype, and I meant to say 7,200. I was conceiving of it more as a square. I'll make that correction.

This is why we all need editors. :)

Beyond that, I think the general point stands.

Thanks for the outpoint.


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