http://en.wikipedia.org/wiki/Pie_chart#Use.2C_effectiveness_and_visual_perception http://en.wikipedia.org/wiki/Pie_chart#Use.2C_effectiveness_... Looks like re

http://en.wikipedia.org/wiki/Pie_chart#Use.2C_effectiveness_and_visual_perception http://en.wikipedia.org/wiki/Pie_chart#Use.2C_effectiveness_... Looks like research has been done. Yes.