Problem-Solving Technique: Step 2- Root Cause Analysis: 3 Leg / 5 Why

“Maybe you are searching among the branches, for what only appears in the roots." - Rumi

Introduction

If you have a broken wrist, it will hurt a lot and the painkillers will take away the pain but do not cure the wrist. You will need a different treatment to help the bones to heal properly. In this example, the problem is a broken wrist, the symptom is?a pain?in the wrist and the root cause is broken bones. So, unless the bones are mended, the pain will not be cured. This example is about physical health but what do you do when it comes down to work?

Objective

Companies that are committed to quality are always looking for ways to improve. When a process is running smoothly, they explore new ways of enhancing workflow. When something breaks down, they take extra steps to ensure a clear?understanding of the problem’s root cause. Instead of simply fixing the surface issue, the 3×5 Why analysis goes deeper to uncover all the layers that created the error in the first place.

In the problem-solving technique (like the 8D Model), one of the most pertinent steps is to find a real reason why that failure/problem/defect has occurred. Once it is adequately identified, the organization can take appropriate corrective action. There are different types of root cause analysis techniques which include 3Leg/5Why Analysis, Ishikawa Diagram, PDCA and many more. ?

Definitions (ISO 9000: 2015)

Complaint (clause 3.9.3): Expression of dissatisfaction made to an organization related to its product or service or the complaints handling process itself where a response or resolution is explicitly or implicitly expected.

Complainant (clause 3.1; ISO 10001: 2018): Person, organization or their representative making a complaint.

Corrective Action (Cl 3.12.2): Action to eliminate the cause of nonconformity and to prevent reoccurrence.

Correction (Cl 3.12.3): Action to eliminate a detected nonconformity.

Detailed Information

Leaders in the management system have developed a variety of methods to improve quality. One of the most frequently cited is “The Five Whys.” Toyota’s?Masaaki Imai?created this management technique in the 1970s, requiring the cross-functional teams to peel back the layers of every problem by first asking why the issue occurred and then why the underlying issue occurred.

Through research, it was determined that it takes five “whys” to truly understand root causes and find long-term resolutions. Instead of focusing on basic issues such as defective parts, the Five “Whys” ensure that the team discover how those parts became defective in the first place, so the entire process evolves.

The following are the 7 key steps for problem-solving.

1.?????? Define the Problem

2.????? Correction, Containment, Interim Action

3.????? Root Cause Analysis: 3 Layered 5 Why Analysis (3L5Y), Ishikawa Diagram, PDCA

4.????? Implementation of Corrective Action

5.????? Effectiveness Evaluation

6.????? Horizontal Deployment

7.????? Documentation, Lesson Learned and Promotion of Awareness

Read More: https://bit.ly/ProblemSolvingTechnique

It is common for employees to resist process changes, and the transition to 3×5 Why Analysis may have its opponents. It is far more time-consuming than putting a quick patch on the surface problem. The organization should provide its employees with the training and tools they need for success with the new quality philosophy.

Read More: https://bit.ly/CorrectionContainmentInterim

The following are 7 key questions related to root cause analysis (3 Legged 5 Why: 3L5Y). They are,

1. What is a 3-legged 5Why?

• Leg #1 – Occurrence
• Leg #2 - Detection
• Leg #3 – Systemic

2.????? Why use the 3L/5Y approach?

3.????? When to use the 3L5Y?

4.????? What if systematic root cause analysis is not conducted?

5.????? How many Why should you ask?

6.????? What should NOT be the final Root Cause?

7.????? Example of 3L/5Y approach

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1.??? What is a 3-Legged 5 Why (3L5Y)?

A problem-solving tool that systematically drills down to the real root cause to effectively find the Root Cause by analyzing cause and effect relationships and solves chronic and/or systemic problems.

• Occurrence leg?– Why did this situation occur? Repeat five times, ensuring that each why points back to the previous answer.
• Detection leg?– Why was this situation overlooked? This leg examines why existing quality control procedures failed, allowing organizations to address this area of the process as well. Repeat five times, ensuring that each why points back to the previous answer.
• Systemic leg?– Why did the systems in place permit the error to occur? This leg looks at the larger perspective for conditions that made errors possible. Repeat five times, ensuring that each why points back to the previous answer.

?2.??? Why use 3L/5Y Approach?

• Provides a road map to a permanent corrective action.
• Stops the problem from happening again, both safety and quality issues
• Increases employee and customer satisfaction.
• Increases quality, profitability, and market share.

As per Edward Deming, “85% of the reasons for failure to meet customer expectations are related to the deficiencies in the system and processes … rather than the employees.”?

3.??? When to Use 5 Why:

• Customer Issues: Complaints, Rejection, Recall and Warranty issues.
• Supplier Issues: Quality, Delivery, Warranty, Recall
• Internal Issues:

§? Informal complaints including Field Engineer Incident reports.

§? Quality system audit issues

§? First Time Quality (FTQ)

§? Internal Quality Issues

4.?? What if Systematic Root Cause Analysis is not conducted?

• Customer dissatisfaction
• Uncompetitive/nonconforming performance
• High cost of failure
• Potential loss of business
• Recalls/Warranty

5.??? How many Why’s should you ask?

• Ask “Why” until the root cause is uncovered.
• Maybe more than 5 Whys or less than 5 Whys
• If you don’t ask enough “Whys”, you may end up correcting a “symptom” and not a “root cause.”
• A root cause is usually a process, policy, design, or person.
• There can be more than one root cause.

?6.?? What should NOT be the final Root Cause?

• Human error is an inadequate “Root Cause” because it does not address the true reason the failure occurred.
• Retraining employees is often the corrective action. This does NOT solve the actual root cause!!! The defect occurs again because the true Root Cause related to the ‘manufacturing issue’ was NOT found as the team did not get to the CORE of the Root Cause!

?7.????? Example: 5Why Analysis:

1.??? Occurrence “leg #1” – Why did the specific problem occur?

• Process related questions.

- Was the correct process used?

- Was standardized work followed?

- Was the person performing the work trained?

- Has anything changed recently in the process (4M Change)?

?

• Product/Part related questions

????- Was the correct part used?

????- Has there been a product change?

????-?Are parts handled and stored correctly?

• Tooling related questions

- Was correct tooling used?

- Is tool change/maintenance being followed?

- Are tools in good working condition?

2.??? Detection “leg #2” – Why did we not detect the specific problem?

• Why did the problem reach the customer?
• Why did we not detect the problem?
• How did the controls fail?

?3.??? Systemic Problem “leg #3” – What was the system breakdown that allowed the specific problem to occur?

• Was the failure mode identified in PFMEA?
• Was the new product/process planning process followed?
• Was the risk of failure mode occurring predicted properly?
• Was the risk of not detecting the failure mode predicted properly?
• Is the design of the product robust as it relates to failure modes of root causes?

Read More: https://bit.ly/Step1DefineProblem

Industry Challenges:

• How often the organizations are aware of the root cause even before conducting the 5Why analysis?
• How many organizations believe in 3L/5Y (Occurrence, Detection, Systemic) and utilize a cross-functional team for the analysis?
• How often is the corrective action based on the root cause, not the symptoms?

References:

IATF 16949: 2016

ISO 9001: 2015

ISO 9000: 2015

OEM Supplier Manual

CQI 20: Aug 2018, 2nd Edition (Effective Problem-Solving Guide)

Industry Experts

Nexteer Training Material