Most people probably don’t know that pie charts have been around since at least 1801 when it was used by William Playfair to present geographic and economic data for European States. While we may all know the chart as a pie the French referred to it as Camembert (soft round cheese) (Few, S. 2007).
Pie charts may give a pie chart the name of a tasty food, for as long as I can remember I have always had a love/hate relationship with them. They look pretty and neat and clean and can make your slides look colorful and even impressive. However, whenever I have sat in a presentation and pie charts have jumped onto the screen I always seem to struggle to understand what exactly I am looking at. At some point I kind of wonder if it’s just me and as I look around the room I see people squinting, straining and stretching their necks to take in, comprehend and scrutinize what exactly is being presented to them.
To be honest, when there are just a few percentages being represented the experience can be quite good and this is especially true when it’s easy to see the break down (i.e. 75% to a 25% at a very obvious 90degrees right angle). However, when the pie chart starts to incorporate multiple breakdowns, understanding the magnitude of difference as well as figuring out the size of tiny segments becomes extremely different. This whole experience is magnified when you have to start moving your eyes from the legend on the side (which very often is small and hard to read) and then back to the pie chart itself.
In my world, bar graphs are much better and if you need any more convincing read ‘Save the Pies for Dessert’ by Stephen Few.