Produces an iceberg that moves a problem down four levels of causation - from the visible event, to the pattern over time, to the underlying structures, to the mental models that hold them in place - pairing each level with the intervention it implies to find systemic causes and higher-leverage fixes. Use when a problem keeps recurring despite event-level fixes, when a symptom is being treated as a one-off, or when the question is why this keeps happening and where to actually intervene.
