Five whys helps in identifying the root cause of a problem by determining the relationship between different root causes of a problem. It can also be used to understand the reasons for a positive outcome or goal.
Use the five why technique to ensure you have identified the actual causes of a problem. You may need to ask more than five whys to find the causes, and you should consider if a cause could have been prevented. For example, if you see "human error" as a root cause in RCA, it may be indicating a lack of check or fail-safe mechanism. Therefore, you should always ask why the human error was possible.
5 Whys approach
Five whys is useful as it provides a consistent approach to understanding causes. It helps overcome assumptions that we might have. The process is easy to learn and use, either as an individual or with a whole team. Five whys should be applied in a blame-free way, where the focus is on finding the "why" rather than blaming "who".
- Identify the problem
- Ask why the problem happened, and record the reason.
- Decide if the reason is the root cause
- Could the reason have been prevented?
- Could the reason have been detected before it happened?
- If the reason is human error, why was it possible?
- Repeat the process using the reason as the problem. Stop when you are confident that you have found the root causes.