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%:

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.

Source: WTF Visualizations

Going further

On a daily basis, the website WTF Visualization shows visualizations that make no sense. Check it out or follow them on twitter.

Percentages don’t add up to 100%

Values don’t match visuals

Going further

Dataviz decision tree