The Wall Street Journal broke one of Edward Tufte’s big taboos in a graphic on the severity of the current recession.
Here’s the culprit:
The problem is that the typical person looking at this will focus on the size of the triangles – so their area should be important to the idea being conveyed. But it isn’t. So, the graph has a huge “lie factor”.
The areas of the blue triangles are arguably the largest in 3 out the four panels (and a close second in size in the third panel).
Let’s think about what this means for the panel on GDP. Severity, on the vertical axis, is the important variable. The current recession is the mildest of the three shown on this count. Duration, on the horizontal axis, is a far les important measure of the economy’s problems. Here, the current recession fairs much worse.
To put this in words: the current recession took a lot longer to get almost as bad (but not quite) as the other two.
I submit that the reporter wouldn’t have had much of a story if they’d written that sentence out and thought about what it meant.
But, put it in a graph, combine a primary variable with a secondary variable, and add shading, we get a triangle that rather blurts out that the current recession is the worst overall.
But that isn’t what’s being shown at all. Let me offer analogy.
This chart is sort of like measuring the braking of a speeding car. The reduction in speed is the severity variable: the faster you’re going the worse it is to have to slam on the brakes. The horizontal axis will still measure duration, but now of the braking: braking for a long time isn’t a good thing, but it isn’t quite as critical as how you fast you were going. What the graph is saying is that it is worse to be driving slower, and to take a longer time reducing your speed. Tell that to your passengers the next time you have to lock ‘em up.
The core problem with this graphic is the impulse to connect the dots and shade the interior. They hypotenuse of each of these triangles actually contains important information: how far we’ve fallen, and how steep is the slope we’re sliding down. But, if we’re only talking about that line segment, there’s no need to form a triangle (or even a basis to call that line segment the hypotenuse – you only think of it as a hypotenuse because the triangles are being spoon fed to your brain). So, problem 1 is connecting the right endpoint of that line segment back up to the horizontal axis. Think about it: you’d only do that in a math class if they told you the question was about a triangle – you wouldn’t do it for the heck of it. But, having done that, the author goes one better and shades the triangle they just pulled out of thin air. The scary thing is, they don’t even have a triangle yet because there really isn’t a good basis for using the horizontal axis to connect the points other than that it just happens to already be there!
Lastly, let’s talk a little bit about the psychology of recessions. Turn the clock back to say 2005 and imagine you knew a recession was coming with certainty, but could steer the economy to one of two kinds of recessions. The two kinds have equal severity, but one takes less time to develop, while the other one takes longer. Which would you choose? My guess is that it would be about an 80/20 split in favor of the more slowly developing recession.
Don’t believe me? Then ask yourself how people felt last September when this recession switched from a very slowly worsening one to a quickly worsening one. Do you remember anyone being relieved? I didn’t think so.
In sum, recessions are no fun, and this one is a doozy. But to improperly emphasize that with weak thinking qualifies as pessimism porn.
Caveat 1: this is a pretty bad recession, and these charts only show some of the worst recessions, so if we showed all of them the current one would not compare well.
Caveat 2: duration of recession is a problem, but it is secondary when compared to the reported severity, so combining them to show duration-severity actually diminishes the point the author is trying to make.
Caveat 3: because this recession started out mildly and then shifted into overdrive, the triangles aren’t an accurate depiction anyway. Instead, something like a scooped-out triangle or even a crescent would make for a more realistic (and smaller) blue shaded area.
