I find pie charts so tiresome. In an exchange with an author who thought they were a good idea, I was looking at the multi-coloured, three-dimensional, textured shading of a few segments of his pie chart, and thinking that this is such a waste of space. As I long ago learned from reading Edward Tufte’s work on the art of visualizing quantitative information, if a graphic takes up more space than a text explanation, it is probably not needed.
My students sometimes say, in defence of a pie chart, that pictures are good; “a picture can paint a thousand words”, they say. “Ha!”, I scoff. There are many pictures that are more eloquent than a thousand words. But a pie chart paints about 6-12 words. It tells me that most things were in one category and the remainder were not. Or another pie chart tells me that things were roughly evenly distributed. But it tells me nothing interesting and with no accuracy, unless it is annotated with information that I would have preferred to read as text.
I was wondering why pie charts are so popular and suddenly realized that they were the graphical equivalent of bling. Maybe there is a role for them somewhere, but I do not think they are a part of serious communication.
Here are a couple of more detailed critiques of pie charts: