For our first #EvalTuesdayTip of 2024, we’re sharing a great data visualization (data viz) resource from Excel Campus about when and how to use pie charts.
Pie charts are controversial among data visualization experts, with some advocating for sparing pie chart use and others advising to avoid pie charts at all costs. The Excel Campus article, written by Microsoft Excel MVP Jon Campora, takes the former position, suggesting, “Pie charts should be used about as often as you should eat pie: occasionally.”
The article is comprehensive and a great resource for data viz beginners, first laying out exactly what a pie chart is and then establishing some basic rules for when pie charts are (and are not) appropriate, such as: A pie chart will only work when the data in question adds up to 100 percent.
The article then illustrates seven examples of badly designed pie charts, and how each bad chart can be “made over” into a good chart – pie or otherwise. For example: Pie charts are hard to read when all the pie pieces are of similar size, and such charts often work better as bar charts.
The post also emphasizes one of the most important laws of the pie chart universe: “Exploding 3D pie charts are always an absolute no,” unless your boss gives you no other choice.
“If your boss insists and you have to use [a 3D pie chart],” the article advises, “make sure you use the smallest number of slices possible and reduce the rotation so that you are looking at it from above rather than the side.”
This article is well-written, informative, and fun to read – a perfect way to start off your evaluation year.
