A defined metric with a named owner, a target or threshold, and a decision that changes when it moves.
A KPI is a metric that passes one test: if it moved sharply tomorrow, a named person would do a specific thing. Most organisations report forty numbers and have five to ten that pass. The rest are diagnostic metrics, read when a KPI moves. See KPI versus metric versus measure.
A defined metric becomes a KPI when it has a named owner, a target or threshold, and a decision that changes when it moves. The test for any number: if it moved sharply tomorrow, who would do what?
Value coverage at cadence, owned by the sales director, target 85 percent; below 75 for two weeks triggers a review of uncovered top accounts. Calls per day fails the test: nothing follows from it.
Forty numbers called KPIs, none owned. Most are diagnostic metrics and belong one level down.