Why PIE CHARTS are the worst? What should you do instead?

We all love our Pies! Chocolate, Pumpkin, Apple… They are delicious and yummy! but god!! They are not yummy when you represent data with them. The human eye struggles to accurately determine quantitative values in a two-dimensional space. Said more simply: pie charts are hard for people to read. When segments are close in size, it’s difficult (if not impossible) to tell which is bigger. It is even harder in 3D!!

Let’s understand the science behind the human eye. The human eye is primarily designed for object recognition and navigation rather than precise measurements. Also, the human eye has very limited spatial resolution meaning it can only distinguish fine details up to a certain degree. When it comes to small angles or fine circular objects, it becomes challenging to differentiate between subtle differences in size or curvature.

Take a look at the below graph and tell me which portion is the largest?

If you answered “Portion A” then it is because human eye is not wired to quantify two circular objects and certainly not 3D sector of a circle.

So, what should you do instead? One idea is to replace the pie chart with a horizontal bar chart in higher to lower order, but you can highlight any order you want according to the story you are telling. With bar charts, our eyes compare the end points and see the trend. Because they are aligned at a common baseline, it is easy to assess relative size.

An alternative to using a pie chart is converting it into a Waffle Chart, (which I will discuss further in my upcoming stories). Waffle charts allow you to represent the percentage of each portion in a square format. By employing different colours, you can effectively highlight the portion percentage using darker shades while visually distinguishing the remaining portions with gray. This approach offers a more engaging and informative way to convey data compared to traditional pie charts.

If you absolutely must use a pie chart, I recommended to limit it to a maximum of two categories. Additionally, ensure that the portion sizes have a clear and significant distinction between them. The closer the sizes of the portions, the more challenging it becomes to discern between them effectively. By this, you can improve the clarity and readability of the pie chart presentation.

In conclusion, while pies may delight our taste buds, pie charts might not be the most delightful way to present data. Understanding the limitations of pie charts and exploring alternatives like horizontal bar charts and Waffle Charts empowers us to create more effective visualizations that aid in conveying information accurately and engagingly.