Take a chart from a real news article. Ask: what's the y-axis? Does it start at zero? What time range? What's the source?
Tricks to spot
- Truncated axis — chart that doesn't start at 0 makes small differences look huge
- Cherry-picked range — showing only a friendly time window
- Different scales — two lines on one chart with different y-axes
- Missing source — no source = no trust
A good chart should answer questions, not raise them. If you finish reading and feel unsure, the chart isn't doing its job.