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Problem Solving Techniques - 5 why or Fishbone diagram ?

Q

QAMTY

#1
Hi everybody

Does anybody can share experiences regarding solving problems techniques.

when is better to use 5 why or fishbone.

I have read info on the net, but still have some doubts, I raised this question here because I see lot of users that over the years have used all these methodologies.

My company develops Engineering projects, Design, construction and setup, focused in petrochemical/oil industries, i?m facing now technical nonconformities such as: boiler failures, Pumps failing, vessels leakage, etc.

Than i?m now starting to do cause analysis in the nonconformities

Please shed light on me

I appreciate your help

Thanks to all
 

yodon

Staff member
Super Moderator
#2
I don't think one method is right for ALL cases. It's going to depend on the situation, the complexity of the problem, the personnel involved, etc.

(And don't forget there are other methods for assessing causes: fault tree analysis [FTA] and even FMEAs.)

Some people are put out by the formality of methods like Fishbone. And if you don't have buy-in, it will be tough to get meaningful results. In my experience, though, when the problem is more complex and needs a more disciplined approach, a more formal method (like fishbone or FTA) helps.
 

Jen Kirley

Quality and Auditing Expert
Staff member
Admin
#3
I think the 5-Y is better for simple issues that can be expected to have one cause.

The fishbone diagram is made to take multiple factors into consideration, that is Man-Material-Machine-Method-Mother Nature. With this tool we can begin to appreciate a problem's complexity and avoid a one-size-fits-all approach.

I hope this helps!
 

Marcelo

Inactive Registered Visitor
#4
Not sure if that?s the case, but from experience, part of the problem with quality problem solving is not the techniques used, but a lack of understanding of the quality problem solving "process".

Some suggestion on great related literature:

Root Cause Analysis: Simplified Tools and Techniques, Second Edition - http://www.amazon.com/Root-Cause-Analysis-Simplified-Techniques/dp/0873896920/ref=sr_1_6?ie=UTF8&qid=1411350965&sr=8-6&keywords=root+cause

Quality Problem Solving - http://www.amazon.com/Quality-Problem-Solving-Gerald-Smith/dp/0873893948/ref=sr_1_1?ie=UTF8&qid=1411350954&sr=8-1&keywords=quality+problem+solving

Quality Toolbox - http://www.amazon.com/Quality-Toolbox-Nancy-R-Tague/dp/0873896394/ref=sr_1_1?ie=UTF8&qid=1411350978&sr=8-1&keywords=quality+toolbox
 

John Broomfield

Staff member
Super Moderator
#5
Hi everybody

Does anybody can share experiences regarding solving problems techniques.

when is better to use 5 why or fishbone.

I have read info on the net, but still have some doubts, I raised this question here because I see lot of users that over the years have used all these methodologies.

My company develops Engineering projects, Design, construction and setup, focused in petrochemical/oil industries, i?m facing now technical nonconformities such as: boiler failures, Pumps failing, vessels leakage, etc.

Than i?m now starting to do cause analysis in the nonconformities

Please shed light on me

I appreciate your help

Thanks to all
QAMTY,

To prevent occurrence or stop recurrence of a costly nonconformity you need to remove the root causes from your system.

Fishbone diagrams help the cross-functional problem solving team to record probable root causes in terms of inputs, facilities, equipment, competence, procedure, environment, care or coordination for further investigation.

Asking why five times is a useful test of whether you are actually looking at a root cause within the scope of the system. For example, you may find a new objective needs more than levels and functions to be aware of it such as changes to the processes responsible for its fulfillment. For example, you may find a lack of competence is caused by not recruiting people with the required behaviors or an operator's lack of care for the requirements is due to disinterested leadership.

So, your 8D processes for preventing occurrence of nonconformity and for stopping recurrence of nonconformity probably need both tools.

John
 
#6
Fishbone: For identifying probable causes of the problem (Not actual root cause). This tool can be used when primary cause of the problem is not known / multiple primary causes has created this problem

Why-Why (5-Why) Analysis : To find out actual root cause of the problem. This tool can be used when primary cause is known.


Fishbone can be used to identify what are the primary causes of the defect.
And then you can use 5-Why / Why-Why analysis for further root cause analysis (To find out actual root cause)



Thanks,
Amit:2cents:
 
Last edited:
T

TShepherd

#7
I tend to agree with Amit...

My experience has validated my opinion that the 5Y is most effective to confirm the results of other problem solving methodologies.

To check your engineering thought process which helps to reduce the probability of a return issue.

  • A well written problem statement - to define the scope.
  • The Fish Bone (Ishikowa Diagram) or Story Board - to narrow the scope.
  • 8D, Statistical analysis, ect. - to narrow the scope further.
  • Perhaps a DOE (Graphical) if more than 1 variable is identified withThe ability to turn the problem on & off - to confirm the results.
  • Then a 3L5Y (4L5Y) (5L5Y) (What ever Legged 5Y)to confirm your engineering thought process and address Detection / Preventive measures as developed.
Then again I could be full of ****.

Good Luck,

Tom:2cents:
 
I

ibillwilson

#8
Hello QAMTY,

To deal with process plant equipment issues like you described, you may have difficulty getting by with just 5 Why and Fishbone. If those are the only tools you want to use, though, then I would suggest starting with 5 Why. At each level (1st, 2nd, 3rd Why, etc.), do a Fishbone to make sure you consider all potential contributors. Using the two tools together in this manner might help you avoid the "straight-line-cause" trap. (It can be easy to miss things with 5 Whys if you're not careful.)

Of course, there are many possible improvements over the 5 Why + Fishbone. A few have been mentioned in this thread; in particular, a multi-leg 5 Why sounds like it could do the trick. What I like even better, though, is what I would call a multi-chain 5x5 Why. Unfortunately, I can't post any links that could explain this better, but there are a few on my website (you may be able to see my homepage link on my forum profile here).

If you'd like me to send you a PM with some links that I think might be helpful, please reply here!

Regards, and Good Luck!
Bill

p.s. My first post! :bigwave:
 
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