This is a featured blog post by Amy Cesal, Product Evangelist at everviz. A three-time winner of the Information is Beautiful awards, Amy is an instructor at Maryland Institute College of Art and co-founder of the Data Visualization Society.
Pie charts are used to show parts of a whole for comparison. They should always add up to 100%. If you have more than a few slices they can easily become unreadable.
Their use has been debated as it can be hard to precisely interpret the angle of the slices or understand the difference between small slices. If you would like to switch up your chart visualizations, here are a few alternatives to the pie chart and what they work well for.
Waffle chart
Waffle charts can be easy to interpret since each square represents a fixed amount. It’s easier for people to estimate and compare smaller percentages. Waffle charts work best when each unit is a whole number (think nothing less than 1%) and can get confusing with too many categories.
Stacked bar
Stacked bars are incredibly space efficient. They can also be easy to compare across multiple bars when aligned or connected with sankey-like lines. They still have the downsides of being hard to read with very small percentages or too many categories.
100% bar chart
100% bars emphasize the percentage rather than the whole. If part of you wants a pie chart, but you’d like your reader to be able to make easier and more valid comparisons across groups than they’d be able to if you used pie-chart small multiples, the 100% bar is a great option. They are great for showing small percentages and many categories, unlike the above options.
