I’m an alum of UW-Madison, and have many fond memories of the place (indeed, TwoPi and I met in grad school there). As a bonus, they have a good alumni magazine. But even the best magazines make mistakes from time to time, and the Spring 2009 issue of On Wisconsin includes a graph that is simply wrong.
The graph, illustrating how much time we sleep compared to other activities, appeared in the article “Bedtime Story” (description “Why do we snooze? UW researchers are pursuing an unconventional theory — that our brains downsize while we sleep, getting us ready to face another day.”) Here’s what the graph looks like:
Take a look at the two biggest circles: we spend 36% of our life sleeping, and 19% on other [unlisted] activities. But that gray circle is pretty small — you could fit 3 or 4 of them into the Sleeping circle. I grabbed a ruler and, sure enough, its the diameters, not the areas, that have the 36:19 ratio. The distinction is even more striking when you look at the tiny circles: we spend 36 times as much of our time sleeping as we do on telephone calls, mail, and email and that’s a LOT, but it’s not a ratio of 1296 (as the areas would suggest).
So I created a graph in which the areas are in correct proportion: