Too many digits can distract from a useful difference and imply more certainty than the information supports. Too few can hide the change the reader is trying to understand.
Choose a display rule that fits the quantity and the purpose. Keep the underlying values available where exact detail matters, and explain any formatting that turns a value into a range or an abbreviated label.
Check totals and small values after rounding. Displayed parts may not add exactly to a displayed total, and a small positive value may appear as zero. A brief note can resolve that confusion without filling the page with unnecessary decimals.
Imagine a practical setting.
Consider showing an estimated duration to the nearest useful minute. Extra decimal places may suggest precision the underlying observation cannot support.
Before the next experiment.
Treat an unexpected value as the start of an investigation. Its source and context matter before you decide whether to remove it or build a story around it.
- Match precision to the reader’s task.
- Keep exact values available when needed.
- Check the effect on totals and small values.
Follow a related question
Identify the claims that materially matter.
A plausible answer can still be wrongCompare the same subject under different light.
Light becomes a digital pictureKeep learning
Related background to continue exploring this subject.
NIST: statistical engineering W3C: accessibility, usability, and inclusion
