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?
Quick check
A bar chart's y-axis starts at 95 instead of 0, making one bar look 3× the other. What's wrong?
Detective checklist for any chart
- What's on the y-axis — and does it start at 0?
- What time range is shown — and what was left out?
- Whose data is this — is the source named?
- Two scales on one chart? — a classic way to fake a correlation.
Watch out
Assuming a chart is honest because it looks polished. Slick design and misleading scales coexist happily — always read the axes first.
Where you'll meet this
News graphics, adverts and social-media posts all use charts to persuade. Reading them critically is a core data-literacy skill.
datacritical thinking
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.