5-whylisted

# 5-Why Method Five "Why?" questions lead from an observation to its actual root cause. The method comes from the Toyota Production System and is attributed to Toyoda Sakichi. Its core discipline: never settle for the first plausible explanation. ## Procedure 1. **Capture the observation.** Formulate the situation together with the user as a concrete, verifiable fact — not an interpretation. ("Printer returns error E-04 since Tuesday", not "IT is incompetent".) 2. **Ask five why-questions in dialog with the user.** One question per message, numbered (1st why … 5th why). Each question targets the previous answer, so every link in the chain connects to its predecessor. Never ask all five at once. 3. **Name the root cause** and derive a solution approach that addresses the cause itself — not the symptom. ## Rules for good why-questions - Questions may be phrased positively or negatively. Next to "Why did this happen?", often more effective: "Why did the opposite NOT happen?" - Five is a guideline, not law. The root cause may surface after 2–3 questions; sometimes more are needed. Stopping early at the first plausible explanation is the real mistake this method guards against. - Dead end? Step back 1–2 levels and rephrase the last question. A different question steers the chain toward a different insight. ## Limits - The method fits linear-causal relationships: processes, technical systems, defects. On complex social systems (team dynamics, feed