2. 2
Agenda
S.No. Topic Slide No.
1 Root cause analysis 3-4
2 Some Challenges 5-6
3 5 Why analysis 7
4 When to use 5 Why Analysis 8
5 General Guidelines 9-11
6 Examples 12-13
7 Problems faced during 5 Why 14-15
8 Countermeasures (Correction , Corrective & Preventive Action) 16-17
3. 3
Root Cause Analysis
• It is a method that is used to address a problem or non-
conformance, in order to get to the “root-cause” of the
problem / non-conformance.
5. 5
Some Challenges
• We think too much work is involved.
• Skipping to the solution when the problem hasn’t been clearly defined.
• Blaming Others:
“If they would just pay attention, we wouldn’t have this problem.”
“That’s QA’s Job!”
• Taking the WHO out of it
7. 7
5 Why Analysis
• Five why’s is a Root Cause Analysis Tool.
• Not a problem solving technique.
• The outcome of a 5 Why’s analysis is one or several root causes that
ultimately identify the reason why a problem was originated.
• There are other similar tools as the once mentioned earlier that can be
used simultaneously with the 5 Why’s to enhance the thought process and
analysis.
8. 8
When to Use 5 Why Analysis
• Complaint from the Customer
• Observation from the Customer
• Recurring Errors
• Internal Quality Issue
• Quality System Audit Non-conformances
9. 9
General Guidelines
• A cross-functional team should be used to solve the problem
• Don’t jump to conclusions or assume the answer is obvious
• Be absolutely objective
• Ask “Why” until the root cause is uncovered
• May be more than 5 Whys or less than 5 Whys
• If you are using words like “because” or “due to” in any box, you will likely
need to move to the next Why box
10. 10
General Guidelines
• If you don’t ask enough “Whys”, you may end up with a “symptom” and not
“root cause”.
• Corrective action for a symptom is not effective in eliminating the cause
• Corrective action for a symptom is usually “detective”
• Corrective action for a root cause can be “preventive”
11. 11
General Guidelines
• Any 5 Why’s must address two different problems at
the same time.
• The first part is related to the process that made
the defective part.
(“Why made?”)
• The second one must address the detection system
that was not able to detect the defective part before
it became a problem.
(“Why not detected?”)
12. 12
Example
Example: The vehicle is not starting. (the problem)
Why? - The battery is dead. (first why)
Why? - The alternator is not functioning. (second why)
Why? - The alternator belt has broken. (third why)
Why? - The alternator belt was well beyond its useful service life and not replaced. (fourth
why)
Why? - The vehicle was not maintained according to the recommended service schedule.
(fifth why, a root cause)
COUNTERMEASURE: Create and maintain a schedule of regular maintenance for the vehicle.
13. 13
Example
Example: Final assembly time exceeds target (the problem)
Why? - According to the Pareto chart, the biggest factor is operators needing to constantly
adjust Machine
Why? - Because it keeps having alignment problems
Why? - Because the seals are worn
Why? - Because they aren’t being replaced as part of our preventive maintenance program
Why? - Because seal replacement wasn’t captured in the needs assessment
14. 14
Problem faced During 5 Why
• We generally stop at symptoms rather than going on to lower-level root
causes
• Lack of support to help the investigator ask the right "why" questions
• Getting right answer for the "why"
• Different people using 5 Whys, come up with different causes for the
same problem
• Tendency to isolate a single root cause, whereas each question could
elicit many different root causes
15. 15
Problem faced During 5 Why
Solution
• Verify the answer to the current "why“ question before
proceeding to the next.
16. 16
Countermeasure - Correction
• Action to eliminate a detected non conformity;
• The immediate action taken to correct a problem , usually to allow data to
be reported to a customer
• Examples include:
• Making an adjustment
• Fixing a mistake
17. 17
Countermeasure – Corrective & Preventive Action
Corrective Action
• Action to eliminate the cause of a detected non conformity;
• Must establish a root cause
• Must address the root cause
Preventive Action
• Action to eliminate the cause of a potential non conformity or a needed
improvement.
• It is a proactive process to identify opportunities for improvement rather
than a simple reaction to identified problems or complaints.