A percentage says how one amount relates to another. Without the denominator, the reader may not know whether the figure describes all visitors, completed tasks, or a selected subset.
Write the group beside the percentage and check whether that group changed between comparisons. A rising share can happen while the underlying count falls if the total falls more. Counts and proportions answer related but different questions.
When comparing percentages, distinguish a change in percentage points from a relative percentage change. State the starting value and the method of comparison. A clear denominator gives a small number enough context to carry an accurate explanation.
A small working example.
Imagine two groups completing different numbers of attempts. A completion count alone cannot establish the same comparison as a rate with its total shown.
A note to keep beside it.
Show a reader how to question the result. A date, an explanation of coverage, or a visible range can make a chart more useful than extra precision.
- Name the group behind the percentage.
- Compare counts as well as shares.
- Distinguish percentage points from relative change.
Follow a related question
Identify the behavior being tested.
What an environment is forCompare one object under two light sources.
A color depends on the lightKeep learning
Related background to continue exploring this subject.
NIST: statistical engineering NIST: the International System of Units