Chapter 3 of 10All chapters
Chapter 3 of 10
Area and 3D
Encodings people misread.
Squared errors
Doubling both the width and height of an icon or bubble quadruples the area, and readers respond to area. The visual change is twice the real one.
- Bubble charts should scale by area, and people still underestimate them.
- 3D effects add perspective distortion favouring whatever is at the front.
Volume is worse
Three-dimensional objects cube the effect. A pictogram scaled in three dimensions to show a 2x change looks like an 8x change.