My second year of med school, I nearly failed my pulmonary class. The reason was that I decided to celebrate my 29th birthday by driving to Chicago to attend Edward Tufte’s one-day course on Presenting Data and Information–totally worth it and I’d do it again. I not infrequently find myself in journal clubs where the rest of the group is, say, expressing their horror at the promiscuity of a kinase (yeah, that’s a thing), and I’m going “Look how they scaled their axes. How are we supposed to take these authors seriously?” My reputation for graph-related crankiness has grown to the point where colleagues send me examples of really horrible graphs–this one just gets better every time I see it. But I’m not using this post to make impassioned pleas to the scholars and scientists of the world to pull themselves together and learn how to use error bars for crap’s sake (I mean, really how hard is it?). Today I am appealing to jokesters.
Joke charts are wonderful comedy. Wonderful. But if you don’t make a readable chart, no one’s going to get the joke. Cause the chart is the joke, so to get the funny you have to understand the chart. See? The inspiration for today’s impassioned plea was none other than Matt Yglesias, who recently published the following:
I’m an Yglesias fan, and this is a genuinely funny idea. But I didn’t laugh when I saw it, because I couldn’t figure out what the hell was going on, and by the time I could, I felt more like crying. The point of the figure is that until last month or so, there hadn’t been a living ex-pope for a really long time. The joke is supposed to be that for 999 years, the number of popes per year holds steady at one, and then in 2013 the number jumps up to two. If that’s not immediately obvious, it’s probably because, thanks to the poorly chosen tick mark intervals on the y axis, that big horizontal line clearly tells us that the number of popes has held steady at some number between 0.9 and 1.2.
As to the years…well I thought that was just a stream of random digits at first (pro tip: if you need to label your axis “year” to clarify, your figure might have issues). On closer inspection we realize that it is representing the numbers 1013 to 2013 with a tick mark every fifty years. Not super useful–I don’t orient myself to the passing of centuries using the year 1513. Actually, I use the year 1517 when Martin Luther nailed up his theses, because that’s what my Modern European History teacher told me to do, but surely it would be simpler for most people to use the year 1500? And then for some reason there is not one data point for 2013 but a whole column? Representing, I suppose, that there are simultaneously all possible numbers of popes between one and two, a phenomenon known as Schroedinger’s Pontiff?
There’s also one last small problem, in that the data are incorrect (see Pope Gregory XII, who resigned in 1415, ending what Medieval scholars call the Belt and Suspenders Period* during which there were two popes all the time for 39 years). But that’s a topic for another day.
Now consider and compare, if you please, two different versions of a pie chart gone viral in support of marriage equality (yum..viral pie).
As with all good memes I have no idea who created these (Option A came from here, and Option B came from here). But the way I imagine it, Option B’s creator looked at Option A and said, “Holy farts, why is that pie chart in 3-D?” Option B’s funnier anyway.
Another example of pie charts gone awry is this one, which was published by HuffPost Comedy before election day 2012:
I really want to love this one. But I just can’t laugh at a pie chart that is not only gratuitously 3-D, but rotated on its side at some bizarre angle like the pie took a self-portrait for its OkCupid profile. Wedges are not the ideal method for representing relative quantities, but plumping and rotating them makes it even harder. Especially when those wedges are too small for the labels, necessitating that the rotated/angled pie be covered in pointers like an electrocuted hedgehog. This would have been an equally hilarious but much less fatiguing bar chart.
In summary, the funniest part of a joke in chart form is the quantitation. Otherwise, you could just type up the Internet’s billionth top-ten list. If you want to communicate quantities, you have to make a nice, clear, economical chart, same as everybody else. And then add the farts.
*Medieval scholars don’t do that.