Pie charts are simple, and everyone thinks they are great at showing you percentages, but they really aren’t. We don’t use them in our visualizations, and we don’t think you should, either. In this brief article, we’ll show you why.
This pie chart works because you have three products with radically different sales numbers, so it’s easy to see first, second and third place.
If the sales numbers are closer, the pie chart stops working. In this example, all numbers are different, but you can no longer see which slice is the biggest, or which are bigger than the others.
This only gets worse if you add more products:
If you do something fancy, like create a 3D chart, the forced perspective makes reading even more difficult.
It doesn’t get any better when you add axis callouts with the percentages because, if you have to read the visualization, you’ve failed to make your point visually.
Compare this to a bar chart:
Now, astute observers will notice that I sorted the data so that the products are charted by the lowest sales value, making it easier to see that in the bar chart. True, and my point is, if I chart the sorted data with a pie chart, I still have no idea of the sales figures of the products related to each other, as shown below.
Our recommendation: don’t use pie charts. There are better ways to show your data that make the data and relationships between data easier to understand. If you want to know more about analyzing data and creating great data visualizations, and how to start your data science journey, see our page Data Analysis and Visualization for Career Growth.