Exploring Composition Snapshots – Pie Charts

Although pie charts are quite often used, in the author's personal experience and the opinion of industry leaders in the field of data visualization, they are best avoided in reports/dashboards because it gets difficult to draw insights accurately from them. Pie charts often confuse even the best in the business. Notice how it is easy to trick people with the following pie chart (tricking people is not what we as data analysts/visualizers are supposed to do):

Figure 4.39: Sample pie chart

The goal of the pie chart is to display market penetration levels for brands A, B, and C. A simple visual inspection may cause one to believe that Brand A and C have equal market penetration, but in reality the difference between them could be several millions of dollars due to a couple of percentage points' difference. Therefore, it is recommended not to use pie charts. That said, if there is no way to avoid using...