Root cause: what it is and what it means

The root cause is the most upstream condition of a problem: once corrected, it prevents the problem from coming back. It is recognized with a double test — if corrected, does it prevent recurrence? Is it under management's control? — and must be distinguished from the immediate cause, which is the visible effect closest to the symptom, and from the contributing factor, which raises the probability of the event but does not generate it on its own. Useful root causes are specific and reasonably identifiable; when the condition identified lies outside the control of whoever is doing the analysis — the customer, the market — it is not a root cause but a constraint. A cause that carries a person's name has not yet passed the double test.

Distinctive: prevents the problem from coming back
Distinctive: most upstream condition of a problem
Essential: double test
Essential: under management's control
Essential: specific and reasonably identifiable
Constant: distinguished from the immediate cause

Glossary

Root cause

The most upstream condition of a problem which, once corrected, prevents it from coming back, and which is under management's control, not a person's.