Monday, November 22, 2010

Deceiving graphs

I was surprised find someone on the TED talk circuit use a classic example of graph distortion that advertisers like to use to make the growth of sales look bigger than it actually is. Here's how they do it. (I'm using Sketchpad to demonstrate it.)
Circle C is almost 16 times
bigger than circle A.
Since the money total in 2000 is double that of 1990 it makes sense to show visually this doubling effect. If you want to enhance it and make it more than just mere doubling then use a circle graph where doubling the diameter actually produces an area that is 4 times larger as I did in this Sketchpad sketch I made.

In the actual diagram used in the TED talk, the diagram was definitely not done to scale. The area of the largest coin is 7 times bigger than the smallest coin though the amount is only 5 times bigger. Not outrageous but still misleading.
Scenes #38 (11.22.10)

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