Not all problems have a single root cause. If one wishes to uncover multiple root causes, the method must be repeated asking a different sequence of questions each time.The method provides no hard and fast rules about what lines of questions to explore, or how long to continue the search for additional root causes.
Thus, even when the method is closely followed, the outcome still depends upon the knowledge and persistence of the people involved.
When to use 5 Why Analysis?
You can use 5 Whys for troubleshooting machines, quality improvement if products , and problem solving of repeated errors or Issue’s but it is most effective when used to resolve simple or moderately difficult problems.
It may not be suitable if you need to tackle a complex or critical problem. This is because 5 Whys can lead you to pursue a single track, or a limited number of tracks, of inquiry when, in fact, there could be multiple causes. In cases like these, a wider-ranging method such as Cause and Effect Analysis or Failure Mode and Effects Analysis may be more effective.This simple technique, however, can often direct you quickly to the root cause of a problem. So, whenever a system or process isn’t working properly, give it a try before you embark on a more in-depth approach and certainly before you attempt to develop a solution.
It is often associated with Lean Manufacturing , where it is used to identify and eliminate wasteful practices. It is also used in the analysis phase of the Six Sigma quality improvement methodology.
How to do 5 Why Analysis
1)Assemble a Team
2)Define the Problem
3)Ask 5 why
4)Know when to Stop
5)Find The root Cause
6)Monitor Your Measures.
Asking “Why?” is Simple but answering it requires serious thought. Search for answers that are grounded in fact: they must be accounts of things that have actually happened, not guesses at what might have happened.
Examples of 5 Why Analysis
Some other methods are1 – Why (symptom)
2 – why (Excuse)
3 – Why (Blame)
4- Why (Cause)
5- why (Root Cause)