Why Why Analysis | 5 Why analysis method with example

What is Why Why ANALYSIS?

→ "Why-Why" analysis is an analytical method that is designed to help you identify all factors contributing to a problem one by one in an orderly fashion, rather than a hit-and-miss attempt to work out the factors and finally, we will have the root cause for the failure.
→ Sakichi Toyoda developed this technique and firstly used it within the Toyota Motors.
→ It is a critical component of problem_solving training and also the same was delivered as part of the induction training into the Toyota Production System for the newly joined employees.
→ This method is also used during the implementing of Kaizen, Lean Manufacturing, and Six Sigma projects.
→ Before going further we will discuss some fundamental concepts which are very important for understanding the 5 why method.
→ 90% of problems can be solved only by why-why analysis.
→ The remaining 10% of problems need a high level and complex methodology for solving.
→ Understand the issue – observe the issue closely, at the spot, on the actual thing, and collect all related information.
→ Problem observation will lead to a conclusion
→ The conclusion may lead to the root cause or will lead to the starting of the 5 Why method.
→ This method is a very famous Root Cause Analysis Method.

Why problem analysis is required?

→ The problem analysis is required to prevent the recurrence of the failure.

→ To find out the root cause and we can easily take preventive action against that.

→ It is also very helpful for developing our problem-solving skills and mitigating future challenges.
You can refer to this article for a better understanding of Various Problem Solving Methods

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What is the problem, cause, root cause, and countermeasure?

→ The problem is what has happened. or it is an undesirable event.

→ Issue Observation is an understanding of what has happened.

→ The cause is the reason behind the failure.

→ The root cause is exactly where the cause has originated.

→ Counter-measure: The action which you take against the root cause so the issue will not be repeated again.

👉 Refer to this article for What is Problem? and Various Types of Solution?

Key Points of Why-why Analysis

→ It should be done in a team
→ Verify facts from Genba – the real place, and on Genbutsu – the real thing.
→ Connect the why-s in a chain of logic
→ Should end up the investigation where the causes can be prevented
→ Use the ‘hence’ logic to check the chain of logic is continuous
→ No assumptions, No guesses
→ Keep management in the loop during the five whys process in the company.
→ Use paper or whiteboard instead of computers because that is a more effective method.
→ Write down the issue and make sure that all people understand it.
→ Distinguish causes and symptoms. Don't mix up causes and symptoms.
→ Keep the focus on the logic of the cause_and_effect relationship.
→ Try to make your answers more precise.
→ Look for the cause step by step. Don't jump to conclusions.
→ Assess the process, not the people.
→ Never consider root cause as "human error" or "worker's inattention".
→ Ask "why" till the root cause is determined.

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How to perform a Why-why analysis?

→ Repeat ‘why’ n-times (till root cause is found)
→ Applicable for one single event
→ Stop the why chain when you reach the basic 5-causes
→ Can be done by Gemba people based on actual findings
→ It is not mandatory to stop after asking 5 why's sometimes we can reach at the root cause by less than 5 whys and sometimes it can go up to more than 5 whys.

Idea of countermeasure

→ Countermeasure is just opposite of the root_cause identified
→ Example:
     ⇢ Final Why - No FG part checking standards are available in place
     ⇢ Counter Measure - Establish and display the FG part checking standard at the FG part checking area.

Example of 5 why analysis:

➨ Problem: Material was not reached at the site on time.

→ Why-01: Why material was not reached on time?
     ⇢ Ans-01:  Because it was dispatched late.
→ Why-02: Why material was dispatched late?
     ⇢ Ans-02: Material was not ready on time.
→ Why-03: Why material was not ready on time?
     ⇢ Ans-03: Material specification reached late.
→ Why-04: Why specification was reached late?
     ⇢ Ans-04: Material specification was not sent with P.O.
→ Why-05: Why specification was not sent with P.O.?
     ⇢ Ans-05: Purchase person missed to send it together.
→ Why-06: Why the person was missed to send it together?
     ⇢ Ans-06: The gap found in the induction process of a new employees.

➨ Root_Cause: The gap found in the induction process of new employees. [Process/System Failure]
➨ Preventive_Action: Introduce a training system for new joiners is updated.

Benefits of 5 Why Analysis:

→ Improving analytical thinking.
→ Develop an understanding of the relation of the failure with theories  & fundamental principles.
→ Improve the knowledge of the function, structure, and mechanism of the equipment/process.
→ Develop the consciousness about the abnormalities causing troubles in the workplace.
→ Aim to level up the ability of the people.
→ Develop the way of prevention of recurrence.

👉 See Also:

➨ All Topics

➨ Lean Manufacturing

➨ ISO 9001:2015 & IATF 16949:2016

➨ 7 QC Tools

➨ MSA, FMEA, PPAP, APQP, SPC

➨ Six Sigma & Lean Six Sigma

➨ QA & QC Topics