June 10, 2008

Dept. of numeracy

Do you have your readers' numbers?

Almost nine years ago, a $125 million spacecraft known as the Mars Climate Orbiter drifted off course during its voyage and was destroyed by atmospheric friction.

Almost unbelievably, the heart of the error was a simple mathematical mistake. One of the contractors employed by NASA used imperial measurement, while another used metric -- and the difference in calculation led to catastrophe.

If mistakes like that can happen in the scientific community, imagine the mix-ups that amateurs can perpetrate when it comes to math! And, in fact, studies show that more than half of U.S. adults have only a basic or, worse, below basic, understanding of numbers.

As I write this, I feel a bit like the pot calling the kettle black because I have a huge discomfort with anything mathematical. Show me a number and my eyes glaze over. I have a hard time understanding exactly what you're talking about and an even harder time visualizing what you mean.

But in what I like to see as a successful case of turning lemons into lemonade, my deficiency has taught me to be exquisitely sensitive whenever presenting numbers to readers. Here are three techniques to consider the next time you need to throw a numeral in your readers' faces:

(1) Bring it down to human scale. A letter from Andrew J. Carra in the July issue of Vanity Fair (the one with Robert Kennedy on the cover) makes this point abundantly clear:

"I wonder how many people can fathom just how much $3-trillion really is," he writes in response to an article called "The $3 Trillion War." Then he explains: "If I were to give someone $3 trillion and tell him that he had to spend $100 million each and every day, seven days a week, 365 days a year, and then told him not to come back to me until he had spent every last penny, said person would not return for approximately 82 years."

As Carra demonstrates, the secret to presenting really big numbers is to break them down so that people like me can actually relate to them.

(2) Put it in context. I recently finished Steven Johnson's fascinating work The Ghost Map, which is the story of London's cholera outbreak of 1854. This non-fiction book is as exciting as a murder mystery, which, in a way, it is. But I digress... Have a look at the author's description of the population of Dickensian London:

"The subdistrict of Berwick Street on the west side of Soho was the most densely populated...that made up Greater London, with 432 people to the acre."

My reaction a reader? Well, that sounds sort of bad, I thought. But then I read his next line."Even with its skyscrapers, Manhattan today only houses around 100 per acre." Suddenly, I got the point.

(3) Give an emotional charge. This technique is suggested by Anne Miller in her wonderful book Metaphorically Selling. "Is a performance ratio of 99.9 percent good enough?" she asks. Then she reminds the reader that a one-tenth of one percent error-rate in, say, health-care services means that 500 surgeries will be botched this week and 12 babies will be given to the wrong parents. (Oops!)

The bottom line? Numbers needn't numb. They can be the most compelling part of your story. Just be sure to treat them with respect -- and use scale, context and analogies to present them in a way that the average, numerically challenged person (like me) can understand.

To receive a short article like this one each week, get on the Power Writing email list. It's free.