You can add silly 3D effects to a pie chart, you can explode all the slices, you can compare multiple pie charts, you can use a legend instead of labeling the slices directly. This will probably render your graph useless, and make you look kind of dumb, but it is not the end of the world-as-we-know-it. But when making a pie chart there is something that you should never ever do, a capital sin that will make you burn in the hell of information visualization: using more than one variable in a single graph.
Well, since we are witnessing the end of the world-as-we-know-it, computer scientists at the University of Utah decided to give a little push, visualization-wise. They are designing a computer application “they hope eventually will allow news reporters and citizens to easily, interactively and visually [analyze] election results, political opinion polls or other surveys”. They boldly state that they “have developed new techniques for exposing complex relationships that are not obvious by usual methods of statistical analysis” (press release). And what are those new techniques? A doughnut chart:
The outer ring labels the series and the inner ring displays the data. Apparently you may add as many series as you wish and you can filter the results by socio-demographic characteristics.
This is the kind of joke that I would expect to be related to April Fool’s Day, but they seem to be serious about it. No one told them that showing part-of-a-whole is one of the few strenghts of circular charts, that when people see 52,7% they see a pie cut in half, not a quarter, that “whole” mean 100%, not 200% or 300%.
Regular readers know that I rarely utter such harsh comments on visualization ideas and applications (I even tried to create a dashboard using Crystal Xcelsius), but this is the stupidest idea of the year. They should know better (here are some tips).
By the way, I found this through a post by Sarah Perez at ReadWriteWeb. She writes: “unfortunately, the poll-analysis software isn’t quite ready for prime time. What a tease!” Fortunately, it is not! And judging from other posts, they could use an information visualization consultant.
Well, perhaps I’m missing something. Am I?