Graphical Perception

Not all quantitative visualizations are created equal. Graphical perception refers to the "visual decoding of information encoded on graphs". Human beings are good at decoding some types of "visual encodings", but not others. For example, we are much better at understanding the relative differences between data points on a linear scale, but not so good at gauging angles or areas. Presenting your information in "easily decoded" formats will help your audience digest the material more accurately and more easily.

In 1984, researchers William S. Cleveland and Robert McGill published a paper quantifying the ability of people to accurately decode different types of visual information. The results of this paper are summarized in this blog post at FlowingData.com.