You read it correctly. How to make a pie chart? You must be wondering why I am even writing this in the first place. Some of you may think pie charts are evil and shouldn’t be used. Some people are still under the illusion that they always make a pie chart correctly.
Do you notice that something is wrong in this pie chart Steve Jobs is using? Let’s come back to this in a bit.
To solve this problem, let me tell you what things you need to know to make a great pie chart.
1. Ensure You Have a Part-to-Whole Relationship
The only goal of a pie chart is to show the part-to-whole relationship in a dataset. To do this, all the values in the data should add up to 100%. Many people do not understand this.
Always check what kind of data you have before you make a pie chart.
2. Don’t Lose the Centre of a Pie Chart
Differentiating between areas of different sizes is one of the hardest things for people to do. The best way to do this is to look at the centre of the pie chart, see the angle of each section and infer its area. If you remove the centre, then the pie chart goes down the gutter.
On this note, meet donut charts. Donut charts are pie charts with a hole at their centre. Donut charts are similar to table tennis, but without table or tennis. They make no sense.
So please don’t remove the centre or spoil it in any way. Keep the centre of your pie chart as neat as possible.
3. Don’t Make a Pie Chart in 3D
Yeah, I got it. 3D pie charts are fancy. However, they’re not correct. Most people make pie charts like this:
Pie charts like these are fine, even though they are wrong, because their 3D format does not spoil their readability. Also it’s just for fun. But when you make the same 3D pie chart for a serious presentation, it’s not acceptable.
Let’s go back to the pie chart Steve Jobs is showing on top. If you observe the above pie chart clearly, you will realize that making the pie chart 3D completely spoils its readability, since the section with 19.5% looks bigger than the section with 21.2%. This leads people to think that Apple has the second largest market share, even though its piece of the pie is actually smaller than Other’s share. So please refrain from using 3D pie charts to ensure accurate data representation.
4. Make a Pie Chart with Clear Colors
Colors play an important role in identifying different pies. So, if a pie chart uses similar colors, it becomes very difficult for users to correctly identify different sections of the pie chart.
Many people use sequential colors in a pie chart, which is very confusing. Always use contrasting colors in a pie chart. It makes the pie chart neater and more legible.
5. Make a Pie Chart with a Reasonable Number of Sections
Pie charts look good when you try to show the contrast between the sections in the pie chart. But many people use pie charts like this:
The problem with this type of pie charts is that they are not understandable. People cannot differentiate between sections with similar areas; they can only differentiate when there are large differences between the areas.
When a chart has more than 4 or 5 sections, it becomes very cluttered and becomes difficult to understand which piece is biggest. Of course, the labels are there to help people understand. But, if labels are necessary for people to understand the pie chart, you should probably use a table to show your data instead.
These are the most important things to keep in mind while you make a pie chart. Hopefully, after reading this, you’ll think twice before making a pie chart. Then, when you do, you’ll make a correct one.
We can’t help you more than this to make a pie chart correctly. But if you have geographical data, we have something better for you. Head out to SocialCops Viz and make map-based visualizations for free.
Also, here’s one more complimentary graph for you for being awesome. Have fun!