The Data Visualization Charting 101 series explores different tools to visualize data. Check out other posts to see which data visualization is right for you.
The most delicious of all charts is the pie chart. I recall a recent TV show where a character made a bar chart of his favorite pies and a pie chart of his favorite bars. This kind of nonsense aside, there are some caveats to using a pie chart, such as that it often requires additional information in order to be useful and that the round shape can take up too much space.
Pie chart basics
- Used to compare the parts of a whole.
- Most effective when there are limited components and when text and percentages are included to describe the content (see Figure 1).
Should you use a pie chart?
There is much debate around the value of pie charts as they can be difficult to interpret because the human eye has a hard time estimating areas and comparing visual angles.
Another challenge with using a pie chart for analysis is that it is difficult to compare slices of the pie that are similar in size but not located next to each other. If you do use pie charts, provide additional information so consumers do not have to guess the meaning and value of each slice.
When designing reports or dashboards, another consideration for the efficacy of a pie chart is the amount of space the pie chart requires in the sizing of the report. Because of the round shape, pie charts require extra real estate, so they may be less than ideal when developing dashboards for small screens or mobile devices. Other charts may provide a better way to represent the same information in less space.
Despite its caveats, is a pie chart the best way to display your data? Learn more about which chart works best for different data sets by downloading the white paper, Data Visualization Techniques.