Use Root Cause / 5 Why when repeat failure, defect, downtime, safety exposure, or process abnormality needs evidence-centered investigation before action.
Investigate to verified cause before assigning action.
Root cause discipline keeps the team from correcting the symptom and calling it done.
CI v9 page
1. Problem statement
State the abnormality, where it happened, when it happened, and why it matters.
Event workspace
Build the Root Cause / 5 Why package.
Capture problem statement, evidence, Why chain, cause validation, corrective and preventive action, verification, sustainment, V.A.U.L.T. retention, and KPI preview.