Thursday, June 28, 2012

Graphics, uncertainty, and the flaw of averages

Many people I know who work in infographics and visualization have traditionally paid little attention to Howard Wainer. It's a shame, as the man is responsible for many fine and elegant books, such as Graphic Discovery and Visual Revelations, and for making William Playfair and Jacques Bertin available again for the lay reader. Quite relevant feats, I'd argue.

I bring Wainer to your attention because right after I finished sending The Functional Art to Pearson/Peachpit, I started looking for inspiration for its follow-up. Wainer is an author I go back every now and then for ideas. A copy of his Picturing the Uncertain World: How to Understand, Communicate, and Control Uncertainty through Graphical Display traveled with me and my family for vacation a few days ago. I am reading it for the second time (first time was when it was released) and enjoying it a lot.

What makes Picturing the Uncertain World so attractive is that it's made of short essays, most previously published in magazines like Chance and the American Statistician. As a consequence, the range of topics is really wide, although all chapters are related —as its subtitle suggests— to the visual display of information. The book has a bit of everything: rants against flawed displays, warnings against the dangers of relying on averages too much, discussions on little known maps by Charles Joseph Minard, and chilling pages about charts designed during the Holocaust. Wainer's style is delightful and witty. Here's a quote I underlined five minutes before sitting to write this post; it should be reminded to every hardcore fan of visual"simplification":

A key tool to understand uncertainty is graphic display (...). A display that shows the data in all their variability acts as a control, preventing us from drawing inferences based only on a single summary number (e.g., an average) that can only feebly characterize a complex situation. Using Sam Savage's delicious phrase, graphs can save us from being deceived by the "flaw of averages."

The funny thing is that I looked for Savage in Google and I found his book, The Flaw of Averages: Why We Underestimate Risk in the Face of Uncertainty. Its website has some informative (albeit a bit crude) animations. I love it when a great read leads you to discover other unknown gems.