Pies are for eating

Bar charts beat pie charts almost every time – I say almost because I am open to being convinced … but I won’t be holding my breath.

Disadvantages of pie charts:
–          pie slices ranking is difficult to see even if attempted
–          rely on color which is an extra level of mental effort for the viewer to process
–          colors are useless if printed in black and white
–          difficult to visually assess differences between slices
–          3-D is worse because it literally makes the nearest slice look bigger than it should be

Advantages of bar charts:
–          easier to read
–          no need for a legend
–          we can rank the bars easily and clearly
–          easy to visually assess difference

If you google “pie charts” you’ll find a bunch of people ranting far worse than me. Here is a good collation of some of the best arguments.

All that being said, data visualization is a matter of taste and personal preference does come into it. At the end of the day it’s about how best we can communicate our message. I wouldn’t dare say we should never use pie charts but personally I tend to avoid them.