Data Visualization - A Misleading Visualization

There is a saying which goes something like “you can make up statistics to prove anything, 84% of people know that”. The assertion is that nobody checks the sources of statistics which is more or less accurate. The lack of fact checking goes double for the recent surge of infographics on the web. I saw one show up on twitter today which I thought was particularly damning in its misrepresentation of statistics.

A poor visualizationA poor visualization

What’s wrong with this? Look at the size of those two circles. The one on the left is shockingly larger than the one on the right. This is done very much on purpose to shock people into thinking that the government is burning through money, that government workers havereceiveda huge salary increase in comparison with the private sector. However the difference isn’t that huge. The ratio between the two should be about 2.38 but if we look at the size of the circles the ratio looks to be closer to 7 or 8.

Small circles inside the large onSmall circles inside the large on

A common mistake made with circles is to double the diameter to represent a doubling in size.Unfortunately,this increased the volume by a factor of 4 and not 2. In this case the ratio is more than doubled so this isn’t the common mistake but a purposeful misrepresentation.

More than a 2.38 ratioMore than a 2.38 ratio

The morale of the story? While data visualizations can tell a story about data you, as the consumer of thevisualization, need to pay attention to the underlying data and not just a pretty picture.