There was a bunch of discussion yesterday about a graph comparing the amount of money spent on veterinary expenses over the last twenty-odd years to the amount spent on human health care over that same span:
There were a lot of dumb things said about this, but really, the worst part of the whole thing is that it’s amazingly badly done. You’ve got the two series represented by different types of plot, gridlines for one vertical scale but not the other, the year labels floating in space down at the bottom, not associated with the tick marks in any obvious way…
This is the work of a professional think-tank worker? What the hell are they teaching in right-wing public policy programs these days?
As a public service, below the fold is a cleaned-up version of the same graph:
I got rid of the distracting grid lines, provided data points with both curves so you can more easily compare them point by point, pared down the horizontal axis labels and associated them with tick marks in a reasonable way. I also got rid of some of the excess clutter, removing the pointless title and making the legend a little smaller.
It doesn’t change the content in any way (and the significance of this comparison remains somewhat dubious), but at least it doesn’t look like it was made by a chimpanzee with Excel. Honestly, it’s no surprise that our political discourse is so hopelessly superficial, given the godawful way the people conducting the debate stumble around presenting information.
(Of course, the two-axis plot is probably sub-optimal to begin with– it would probably be better to normalize both data sets to their 1984 values (or whatever that year is– I guessed), and plot them on a single set of axes. You’d still make the point that they’ve increased at similar rates, and readers wouldn’t strain their eyes trying to figure out absolute numbers. But if you’re going to do the two-axis plot, do it right.)