Beware of Using Pie Charts for Excel Data Analysis
You really want to avoid pie charts when doing Excel data analysis. Oh, pie charts are great tools to teach elementary school children about charts and plotting data. And you see them commonly in newspapers and magazines. But the reality is that pie charts are very inferior tools for visually understanding data and for visually communicating quantitative information.
Almost always, information that appears in a pie chart would be better displayed in a simple table.
Pie charts possess several debilitating weaknesses:
You’re limited to working with a very small set of numbers.
This makes sense, right? You can’t slice the pie into very small pieces or into very many pieces without your chart becoming illegible.
Pie charts aren’t visually precise.
Readers or viewers are asked to visually compare the slices of pie, but that’s so imprecise as to be almost useless. This same information can be shown much better by just providing a simple list or table of plotted values.
With pie charts, you’re limited to a single data series.
For example, you can plot a pie chart that shows sales of different products that your firm sells. But almost always, people will find it more interesting to also know profits by product line. Or maybe they also want to know sales per sales person or geographic area. You see the problem. Because they’re limited to a single data series, pie charts very much limit the information that you can display.