This visualization demonstrates different techniques for facilitating relative vs. absolute comparisons as described in section 12.2.5 of Interactive Data Visualization by Ward, Grinstein, and Keim. For each variation, this graphic shows 10 bars representing values of 10 through 19. The top variation is the worst, requiring the user to make absolute comparisons between the bars - which humans are very bad at. The techniques below that demonstrate different ways to facilitate relative comparisons instead:
- Bounding Boxes: Bounding boxes give a consistent frame of reference to facilitate relative comparisons
- Grid/Tick Marks: Grid or tick marks give intermediate points of reference
- Residuals: By subtracting the average value from each bar, only the relative differences remain
- Reorientation: By simply re-orienting the bars to be stacked vertically instead of horizontally, relative comparisons become much easier