Accuracy is the most important aspect of an infographic design!

Last week, the article The Truth about the Ice Bucket Challenge by Julia Belluz on Vox Media included the infographic, Where We Donate vs. Diseases That Kill Us, that used proportionally sized circles as its data visualization. The problem with this design is that the circle sizes don’t match the values shown. This is a false visualization and significantly over exaggerates the smaller amounts of money contributed to each charity and the deaths attributed to each cause.

This causes problems because readers often just look at the visuals without reading the actual numbers. They start with the assumption that a visualization accurately represents the data. The Vox Media story and infographic already have over 12,000 shares on Facebook, and this is a great case study for designers to understand how important it is to visualize data accurately.

As readers, we see the area of two-dimensional shapes on the page to represent the different values, but design software only allows width and height adjustments to size shapes. Designers make the mistake of adjusting the diameter of circles to match the data instead of the area, which incorrectly sizes the circles dramatically. It takes some geometry calculations in a spreadsheet to find the areas and then calculate the appropriate diameters for each circle. To demonstrate, I created this corrected version of the infographic.