5 Whys

A structured inquiry that repeatedly asks why a specific problem occurred, following evidence toward conditions that a useful countermeasure could change. Five is a mnemonic, not a required causal depth.

The five whys technique follows a problem by repeatedly asking what conditions made it possible. Its value is in resisting the first convenient explanation and connecting the event to a change that could reduce recurrence. Five is a mnemonic; it does not define how many links exist or where a root cause must be found.

Each answer is a hypothesis requiring evidence. Several causes can branch or interact, and a chain can become increasingly speculative as it moves away from the event. Stabilize an immediate problem when needed, investigate the supported paths, and test a feasible countermeasure. The deepest imaginable explanation is not necessarily the most useful or actionable one.

When to use it

When a recurring or consequential problem needs a supported explanation and a testable countermeasure.

How it can help

Helps move beyond a convenient first explanation, provided each link is checked and multiple contributing paths remain visible. Immediate containment can occur alongside investigation.