Module 13 · Project 7 · Due the date on Canvas · Ethics, Privacy & Dashboard Detective · adaptive competency DV21
Misleading chart detective
Mission progress0%
Begin by evaluating base-rate fairness and Simpson's paradox.
Module 13 · Step 2 of 9 · Guided8–10 min
Why this lab Find the mechanics behind three misleading charts so you cannot be fooled by them.
Analyze three suspect visual cases. Identify truncated zero-baselines, mismatched dual Y-axes, and 2D area exaggeration mechanics before they distort decision-making.
- A truncated baseline. A bar carries its value by its length. When the axis starts above zero, bar length is no longer proportional to the value, so a small difference is exaggerated. The repair is to start bars at zero, or to use dots, whose position carries no promise about zero.
- Mismatched dual axes. Two vertical scales whose ranges are tuned independently can make unrelated series appear to move together, or apart. The apparent relationship is a choice of scale, not a property of the data.
- Area exaggeration. Readers judge a circle by its area, and area grows with the square of the radius. When the radius doubles, the area becomes four times as large, so a value twice as big looks four times as big. Scale the radius by the square root of the value.
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