Charts that lie: truncated axes, twin scales and misleading bubbles
Every chart in this quiz uses real numbers, yet each one misleads through its baseline, second y-axis, bubble radius, date range, or scale. Learn to read how a chart encodes data instead of trusting its first impression.
Questions
- Not answered. This chart is titled Revenue is exploding. Rounded to the nearest whole percent, how much did revenue actually grow from Q1 to Q4?
- Not answered. Both panels plot the same seven temperatures on the same axis, which starts at 36.5 °C rather than at zero. In which panel is the truncated axis an actual problem, and why?
- Not answered. A designer keeps the truncated revenue bars but draws a jagged axis break symbol across the base of each one to signal the missing range. Does that make the chart honest?
- Not answered. Revenue moved from 100 to 103 over four quarters and the chart still has to ship. Which of these presentations report that change honestly?
- Not answered. These two panels plot identical numbers against an identical axis range. What is the honest description of the difference between them?
- Not answered. The blue and orange lines cross in 2022. What does that crossing tell you?
- Not answered. Which of these presentations let a reader compare the coffee shop and rent series without manufacturing a relationship between them?
- Not answered. The 2025 circle is drawn with twice the radius of the 2015 circle to show that users doubled. How many times more area does the larger circle cover?
- Not answered. You need a bubble representing a value nine times the reference bubble's. By what factor do you multiply the reference radius?
- Not answered. What is the lie factor of that radius-doubled bubble chart?
- Not answered. A colleague sends this chart with the note Product X is dying, down a third. What can you conclude from the chart alone?
- Not answered. The press release leads with bookings up 42% year over year. What does the chart actually support?
- Not answered. The case count line here is straight and the climb looks almost gentle. What does a straight line on a logarithmic axis mean?
- Not answered. On the same kind of log axis, this curve bends over after week 6. What has actually happened to the weekly case count?
- Not answered. When is a logarithmic y-axis the right choice, and what does choosing it cost you?
- Not answered. You are reviewing a dashboard pull request. Which of these choices break the proportionality between the numbers and the ink, whatever the author intended?