Pie charts or circle charts are circle-shaped charts, that are divided into slices to depict numerical proportions. In a pie chart, the area of each slice is proportional to the represented quantity.
After the bar chart visualization guide, we are continuing with one of the most common charts. Pie charts are widely used in everyday statistics, in the business world, and in education.
In this article, we will give you some tips about pie chart visualization and present you the four mistakes you can commit during the visualization process. If there is no other way to visualize your data, this article will be a good guide for you.
What Is a Pie Chart?
The earliest known pie chart is generally credited to William Playfair’s Statistical Breviary of 1801:
“A table is nearly always better than a dumb pie chart; the only worse design than a pie chart is several of them…” – Tufte, The Visual Display of Quantitative Information
The shape of the graph shows an uncanny resemblance with a sliced pie, hence the name. However, pie charts also have different shapes and kinds, according to the data they want to visualize.
Standard Pie Charts and Donut Charts
Standard pie charts are mostly used to compare part-to-whole relationships in the case of discrete or linear data. Using it with a low number of slices will result in better interpretation.
In addition to pie charts, donut charts are also commonly used circle visualization tools due to the ability to store additional information or style elements.
Pie Chart Guide
Creating a pie Chart seems easy at first glance, but it is actually pretty easy to make mistakes, as you can see it later in this article. We decided to gather four useful tips you have to keep in mind when using pie charts as a visualization tool.
#1 Not for Comparison
Don’t use multiple pie charts for making comparisons. Instead, use a stacked bar chart.This will help you to present your results in a more understandable way. Human perception has its limits, so be careful not to overcomplicate your presentation.
#2 Less Is More
Use only two or three categories on one pie chart and a maximum five. Again, keep it simple and streamlined.
#3 Total Value Must Be 100%
Always check the numbers. Always.
#4 Start With the Biggest
Order slices clockwise starting with the largest part. This will help your audience to recognize the most important information.
Bonus: Create Pie Charts with AnswerMiner
Four Mistakes to Avoid
To visualize your data, using a pie chart can be a good choice, but you need to know how and when to use it. If you google it up, you can find many examples of pie charts, but most of them are somehow incorrect.
On the picture below you can see a bright-colored, informative and easy-to-understand chart. Perfect for strategic business decisions and comfortable for the eye, right?
Now, let’s go through the mistakes one by one.
#1 3D Pie Chart
It seems fancy and modern that you have a three dimensional pie chart, but the only thing you got is more chaos. Distorting the chart and showing data in a perspective will result in faulty percepcion.
A famous example for that can be seen below. The audience can see the green area significantly bigger than it really is. It looks like it is almost the same size as the blue area. Even the human brain has its limits and it is easy to influence this way.
#2 Fifty Shades
Using different shades and opacity also does not make any sense. The aim of data visualization is to make the charts more understandable, not more complicated.
Use monochromatic or balanced, but contrasting color schemes if needed, but keep it simple: less is more.
#3 Place of Legends
Place the data and the legend on the chart, not somewhere besides the chart. It is confusing for the audience if their eyes have to move between the numbers and the chart. However, if you place the numbers in different boxes, align them right.
#4 Exploded Pie
Do not use exploded pie charts. It is harder to compare the sizes of the parts. Do not forget, keep it simple and easy to understand.
Advantages and Disadvantages
Pie Charts are popular and they are easy to understand if you use only two or three categories. They also indicate a part-to-whole relationship between values. Not to mention they look pleasant to the eye with certain color schemes.
The biggest disadvantage of pie charts is that human eyes can only recognize friendly rates like 25, -50,-75, or 100 percent. This is not the appropriate tool to compare quantities or to visualize complex relationships.
Although the above mentioned disadvantages exist, pie charts and donut charts are widely used in popular channels and media. You only have to avoid the mentioned mistakes, and your infographics or your data storytelling will be informative and useful if you are using this tool.
However, there are better ways to visualize your data in AnswerMiner, so you can gain deeper insights and understand possible relationships.
In the end, here is an informal guide on how to create the perfect pie chart: bit.ly/2dbz2ko