The Visual Miscellaneum from David McCandless has been out for a few weeks now, and while it was a previously Recommended Resource, I wonder if perhaps I was mistaken. John Graham-Cumming, a well known computer programmer responsible for many developments in email, spam prevention, and software build strategies, has a somewhat damning review of the book on his website, and of the “Reduce your Odds of Dying In A Plane Crash” infographic (shown above). Just a taste:
1. The term “density” is not defined and in fact he isn't showing a density at all, just the raw total numbers by country.
2. The underlying data is incorrect. The diagram specifically says that it uses “fatal accidents” drawn from this database. Unfortunately, the person doing the visualization has used the total number of “incidents” (fatal and non-fatal accidents). For example, he gives a value of 75 for the number of fatal accidents in Ecuador, whereas the database gives 38. The same applies for all the other countries.
3. He uses circles with dots in the middle to represent the size. So is the value being plotted proportional to the radius of these circles or the area? Not clear. For example, try to compare Russia and Canada; they look about the same. Now look at Russia and India, India looks smaller to me. So what’s the truth?
Very rookie errors, to be sure, although the Circle one has been discussed widely before. What do you think?
Values are proportional to area of course. If it were proportional to radius, you wouldn’t need circles, just a line or bar would do.