“How Charts Lie” by Alberto Cairo

Rules

1. A chart should be considered a visual argument, not an illustration
2. Baselines should show 0
3. Good charts have good scaffolding
4. Pay attention to scale labels
5. Include:
   1. Data source citations
   2. Measurements, units, and scales
6. Never trust a chart that does not disclose its sources

Notes

• Any chart will lie if you are not paying attention to it
• Be wary of means, they can mask extremes
• “Instead, they should design a chart that finds an aspect ratio that neither exaggerates nor minimizes the change. How is that so? We are representing a 35% increase. That’s 35 over 100, or 1/3 (aspect ratios put width first, so in this case it would be 3:1).”
• “A chart shows only what it shows, and nothing else.”