TODAY’S DATA LENS

A bar needs zero.

25 September 2026 One-minute observation

Square soft-grey, black and red Today’s Data Lens card comparing two bar charts of the same values, 50 and 52: one with a zero baseline and one with a truncated axis starting at 49, showing how the truncated axis exaggerates the visual difference.

Observation

Both charts show the same values: 50 and 52. With a zero baseline, the difference is small. Start the axis at 49 and the visible bar lengths become 1 and 3, making the second bar look three times as long. Because bar charts encode values by length, the Office for National Statistics says their axis should always start at zero.

Same numbers. Different ruler.