Digital Analogue

Dishonest graphics

Today we have another installment in our occasional series, "infographics that really are just plain lying". I was looking at an article on climate planning, and stumbled across the graphic at right. Go ahead, look at it. See anything strange?

First of all, the lines are drawn across at the heights of the semicircles, but the semicircles themselves have area, so it's not clear whether we are meant to interpret this linearly or quadratically. That is, are the labelled values proportional to the height of the lines, or the area of the semicircles? If linearly, what on earth is the point of the semicircles? If quadratically, why are the heights of the circles labelled?

Don't you get the impression that developed economies are generating vastly more CO2 than the emerging ones?

In fact if you look at the spacing of the lines, you'll see that they must have meant them to be linear, because the spacing is close to even, as are the numbers. If you do interpret this as a funny-looking bar chart, it's only somewhat distorted: scaled to a maximum value of 54, it would be representing intermediate values of 40 and 24. So even by this (highly generous) interpretation, the graphic designer is fudging to make the developing economies look like less of a contributor.

But when we see area like that, our natural instinct is to interpret it as meaningful. And here we run completely off the rails. If you interpret the semicircles' area as meaningful, the represented numbers (again scaling to a max of 54) are 54, a little over 29, and less than 11. The largest and smallest values in fact differ by a factor of less than two, but are made to look like they differ by a factor of five. This right here is simply journalistic malpractice.

To the right you see an edited version of the graphic that highlights what the dimensions would have been if the designer hadn't been lazy or flat-out lying. The outer semicircle and all the words and light-grey lines are unchanged from the original. But on the left side is a bar scaled to the actual values (red lines mark the correct scaled heights); and in the rest, the two smaller semicircles are scaled so that their areas are proportional to the numeric values reported.

Story's a little different now, innit?

Speaking for many of us: "I tend to ramble when I think I'm saying something intelligent." --Robert Hoekman, Jr.