As part of the Toyota Production System that spread Kaizen worldwide, there is a practice of repeating “why” five times when a problem is identified. This approach is aimed at thoroughly identifying the root cause of the incident to prevent its recurrence.
- It is not something that occurs naturally.
- By setting numbers, it forcefully engages the mind in seeking the cause.
Note that this method is not effective for complex problems where causes and effects are intertwined in a causal loop.
- It is impossible to reach the ultimate root cause.