aware of it often have to hesitate in interpreting a bubble chart because they cannot assume that the scaling correction was indeed made. It is therefore important that bubble charts not only be scaled correctly, but also be clearly labeled to document that it is area, rather than radius or diameter, that conveys the data.

Judgments based on bubble sizes can be problematic regardless of whether area or diameter is used. For example, bubble charts can lead to misinterpretations such as the weighted average illusion, where the sizes of