Everyone who knows me knows I hate pie charts. How could I, you ask, hate such a beautiful visualization of percentage data? Well, i just outright request that people not use pie charts because the charts are often taken far beyond their intent. All of our new and fabulous software allows even the most unskilled person to create amazing charts. And sometimes, or most times, they’re made into 3D, rotating, florescent monstrosities.
The purpose of a pie chart is to clearly display relative percentages. The intent is to be able to quickly determine that one slice of the pie is slightly bigger or slightly smaller than another slice. When a chart has been tilted for dramatic effects, the slices become skewed. I’ve even gone so far as to run (non-probability, convenience sample) tests to see how people interpret 3D pie charts. What I found is that people are unable to determine which slice is the bigger slice! In fact, if you look at the picture here, you’ll various slices, each representing a proportion. What you don’t see, though, is that THREE of the slices in fact represent the exact same proportion. Three of them are 11%, one is 22% and one is 44%. Unless your job requires you to misrepresent data, this is certainly not the way to go.
And that is why I hate pie charts!