In plain English
A relationship in which measurements move together, without proving that one caused the other.
Why it matters
This instrument can help answer a focused measurement question when it is connected to a real objective and read alongside relevant context.
Example
A small organisation records this signal for a defined page and period, then compares it with related instruments before deciding whether to investigate a change.
Common misunderstanding
Correlation can support a hypothesis, but correlation does not prove causation; other changes or events may explain the pattern.