Comparing the Democratic and Republican tax plans.
This chart is from the Washington Post. I don’t like it, so I made a new, better chart. Look:
For some reason, people love looking at and drawing circles, but circles are terrible for displaying comparable quantitative information (for more on this phenomenon see Stephen Few’s paper Our Irresistible Fascination with All Things Circular [PDF]).
Basically, it’s harder to estimate size across two dimensions (by area) than size along one dimension (by length). For instance, the difference between the bottom two Republican circles on the Washington Post’s chart might look like a a 4x difference to some people, when it’s actually 6x. You don’t want to miss out on how ridiculous that cut is!
Circles are sexy, but lines work and communicate more effectively. Do what works.
That said, people share graphics with circles, so…I guess they work in another sense.
By the way, I made this in a Google spreadsheet that you can see and copy here.