Calculation errors

A collection of common dataviz caveats by Data-to-Viz.com




This is probably the most obvious pitfall example of the collection, but is probably the most frequent one as well. Number inconsistencies on a graphic make it completely useless.

Percentages don’t add up to 100%


For example, when displaying percentages on a pie chart, double-check that the percents sum to 100%:



img
Source: WTF Visualizations



Here, alsoe note that using an exploded 3D pie chart is probably the worst way to convey information ever invented. (Read more about it)

Values don’t match visuals


In the following example, the 45% annotation is linked with the biggest part of the donut chart; clearly something is incorrect.



img
Source: WTF Visualizations



Going further


Comments


Any thoughts on this? Found any mistake? Disagree? Please drop me a word on twitter or in the comment section below:

 

A work by Yan Holtz for data-to-viz.com