The 5 why method or the Root Cause analysis method that has been described in the Tools section plays an important role in determining that the X’s are recorded at actionable level. In this implementation of the 5 why tool, there is a slight variation from the standard methodology and hence it has been explained in the context of Actionable X’s below:

5 Why Method

The 5 why method is a non-statistical method to convert vital few inputs to their actionable level. It does not require any elaborate mathematical testing but rather simply relies on brainstorming the reasons and digging deeper and deeper in the process.

Procedure

1. Common Understanding of X’s And Y’s: The first step in the procedure itself differentiated the 5 whys analysis in the case of finding actionable X’s to the five why’s analysis in other cases. Here, the 5 why analysis is usually performed by the entire Six Sigma team rather than a bunch of experts. Hence, it is essential to ensure that everyone has the correct understanding of the vital few inputs and outputs being discussed and that the goal is to reach an actionable level. The facilitator must ensure to reach an explicit agreement on the definition of X and Y as well as eliminate common misunderstandings as soon as the process begins.

2. Brainstorm: The second step is to brainstorm as many possible reasons to figure out what the next step could be. Every member in the team must be encouraged to come up with a unique explanation.

3. Analyse the Responses: Since there are likely to be more than one responses to the 5 why’s question, choice needs to be made. At every stage the choice has the capability of completely changing the focus of the analysis. Hence, common grounds must be reached between the team. A common practise is to select a reason that has least assumptions attached to it.

4. Iterate: Once the agreement has been reached. It is now time to check whether the X is still at the actionable level. If Yes, the exercise should be stopped, if not the exercise must be iterated till the actionable level is indeed reached.

The 5 in the 5 why’s is a mere abstraction. The actual number of iterations required to come up with an actionable X will be less or more. However in almost all cases, actionable levels are reached within 5 iterations.

The 5 whys analysis for finding actionable X’s is therefore a combination of the regular root cause analysis and brainstorming. Instead of relying on expert knowledge, the collective knowledge of the Six Sigma project team is used here.