Check the Axis

Truncated bar charts

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• On bar charts, bars should start at zero.
• Truncated axes exaggerate small differences.
• Always read the axis labels before judging a chart.

Steps

1. Where does the axis start?
2. How much bigger?
3. Line charts are different
4. How much bigger does it look?
5. Percent or percentage points?
6. Two vertical axes