Under the subject line “Blog bait!”, Brendan Nyhan points me to this post at the Washington Post blog:
For 2013, we asked some of the year’s most interesting, important and influential thinkers to name their favorite graph of the year — and why they chose it. Here’s Bill Gates’s.
“I love this graph because it shows that while the number of people dying from communicable diseases is still far too high, those numbers continue to come down. . . .”
As Brendan is aware, this is not my favorite sort of graph, it’s a bit of a puzzle to read and figure out where all the pieces fit in, also weird stuff going on like 3-D effects and the big space taken up by those yellow and green borders, as well as tricky things like understanding what some of those little blocks are, and perhaps the biggest question, what is the definition of an “untimely death.” But, as often is the case, the defects of the graph form a statistical perspective can make it attractive to readers: the 3-D design is grabby, and all the puzzles give a Chris Rock effect. So overall I think the graph’s a winner. And its use of the three colors is excellent—a simple but effective way of conveying the three groups (just don’t ask me to guess the relative sizes of the yellow and red parallelograms!).
The click-through solution
But what the really needs—and this is something I’ve said before too—is for the reader to be able to click through to a more standard statistical graphic (for example, a dotplot showing causes of deaths in order, with three columns corresponding to the three colors on this graph, with smaller, replica dotplots showing results just for the U.S., China, India, Indonesia, and other large countries, also maybe some continents and other groupings such as the E.U.), then click through again to a spreadsheet with the numbers.
Also some hypertext, i.e., a caption for the graph. There seems to be a style thing where designers like to use the minimum of words. But remember the BD principle: a picture plus a thousand words is better than 2 pictures or 2000 words. The hypertext could give lots of information, including their definition of “untimely death.”
This graph does not say what you think it says
Most interesting to me, though, was Gates’s claim that the graph shows that “while the number of people dying from communicable diseases is still far too high, those numbers continue to come down.” I guess I’ll buy that the graph shows that those yellow numbers are “far too high,” not really from the graphic itself but because we can see that big fat rectangle for Diarrhea. It just doesn’t seem like so many people should be dying of that. But I don’t think the graph does such a great job of showing the trend (“those numbers continue to come down). I mean, sure, after seeing Gates’s words, I can go back and say, yeah, lots of bright yellow there. But I didn’t catch that at all on first viewing. Also, that bright yellow thing is a bit of a cheat. For the red and green sections of the graph, the sharpest declines are indicated by a very pale green and a very very pale pink. But in the yellow box, the sharpest declines are screaming yellow.
That’s all fine, of course. The point of a display like this is to get people’s attention. It’s the role of the follow-up graphs in the click-through to provide some perspective and allow some comparison.
Here’s the quick rule:
Infographic: Grabs your attention.
Statistical graphic: Allows you to make comparisons.
Both these goals are important, and there’s no reason whatsoever to expect that they can be most effectively achieved by a single display. Also don’t forget captions. If there’s a key message you want to convey in your graph (for example, infectious diseases kill too many people but are in decline), I recommend putting that message front and center, in words, on your display.
P.S. Funny that they call Bill Gates a “thinker.” He seems like more of a doer!