1. 5 Why analysis
By its very nature, a Lean Six Sigma program requires a number of changes throughout the organization. That’s what we are trying to do right? Change processes.
To change processes we have to change the way people do things. That isn’t easy. We will give you some tools to assist.

2. Five Why Preparation
Five why is a Root Cause Analysis Tool. It is not a problem solving technique. The outcome of a 5 Why analysis is one or several root causes that may ultimately identify the reason for a problem. There are other similar tools (see below) that can be used simultaneously with 5 Why to enhance the thought process and analysis.
Problem
Root Cause
Corrective
Actions
Root Cause Analysis (RCA) Tools:
Ishikawa Charts (Fish Bone)‏
Design of Experiments
Is / Is not Analysis
5 Why
Cause & Effect Diagram.
Statistical Data Analysis (Pareto Charts, Anova,etc…)‏

3. For all the Five Why:
Ask the full question including the problem or cause behind it. For instance, if there is a problem with labeling ask:
Example: “Why were the parts were labeled incorrectly?”
If the answer is unreliable database ask:
“Why is the database unreliable?”
If the answer is database has incorrect information about parts ask:
“Why does the database have this incorrect information?”
And, so forth
If we do not follow this approach to answers to the whys, we will tend to lose focus by the third or fourth why.

4. Who are the best at asking questions to solve problems?
Power of Asking Questions
Who are the best at asking questions to solve problems?

5. Children! Why? Power of Asking Questions
…because they keep asking objective, open-ended questions until the answer is simple and clear
When working with people to solve a problem,
it is not enough to tell them what the solution is. They need to find out and understand the solution for themselves. You help them do this by asking open-ended , thought provoking questions.

6. Five Why’s Preparation
Five Whys – The First Why
A clear statement of the reason for the defect or failure to occur
Understood even by people who are not familiar with the operation where the problem took place.
o not try to justify it, there will be time to do that later on in the following whys if it is pertinent to the thought process.
Write it down even if it seems too obvious for you. (It may not seem that obvious to other people!)
Five Why’s Preparation
It is said that a well defined problem is a half resolved problem; hence it is important to state the problem as clearly as possible.
Whenever possible define the problem in terms of the requirements that are not being met. This will add a reference to the condition that should be and is not.

7. Five Whys – The Second Why
A more concise explanation to support the first statement.
The explanation can branch out to several different root causes here. It is OK to follow each of them continuing with their own set of remaining 3 whys and so forth.

8. Five Whys – The Third Why
Do not jump to conclusions yet, follow the regular thought process even though some underlying root causes may start surfacing already.
This 3rd why is critical for a successful transition between the obvious and the not so obvious. The first two whys have prepared you to focus on the area where the problem could have been originated; the last 3 whys will take you to a deeper comprehension of the problem.
You do not need to answer all the whys at the same time. It is an investigation activity and it will sometimes require you to go to the process and see things you could have missed at first.
You may be missing the obvious by rushing into “logical” explanations”.

9. Five Whys – The Fourth Why
Clear your mind of preconceived explanations and start the fourth why with a candid approach. You may have two or more different avenues to explore now - explore them all individually.
Even if one or several of them turn out not to be the root cause of the problem, they may lead to improvement opportunities.
This is a good time to include a Cause and Effect (fishbone) analysis looking at
Method (process)
Materials
Man (people)
Machine (equipment)
Environment

10. Five Whys – The Fifth Why
When you get to the fifth why it is likely that you have found a systemic cause.
Most of the problems in the process can be traced to it (them).
Even a malfunctioning machine can sometimes be caused by an incorrectly followed preventive maintenance process or incorrect machine parameters set up.
When you address a systemic cause, do it across the entire process and detect areas that may be under the same situation even if there are no reported issues yet.
If you have reached the fifth why and you are still dealing with process related cause(s), you may still need one or two more whys to deep dive into the systemic cause.

11. Five Whys Conclusion
A good way to identify if the 5 Whys was done properly is to try to organize the collected data in one sentence and define it in an understandable manner. If this cannot be done or the sentence is fragmented or meaningless chances are that there is gap between one or several of the whys.
You must then revisit the 5 Whys and identify those gaps to fill them in. If there is coherence in the way that the sentence is assembled, it shows consistency on the thought process.
Something like:
“Problem Description” occurred due to “Fifth Why”. This was caused by “Fourth why” mainly because “Third Why” was allowed by “Second why”, and this led to “First Why”.

12. Five Whys Analysis Three Paths
Specific problem:
Why did we have the problem?
Problem not detected:
Why did the problem reach the Customer?
System failure:
Why did our system allow it to occur?
Once the problem has been defined (as the customer sees it) a cause/effect relationship investigation for each path will help in determining the root cause.