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True Root Cause

Six Sigma – iSixSigma Forums Old Forums General True Root Cause

This topic contains 21 replies, has 17 voices, and was last updated by  shyanji 11 years, 9 months ago.

Viewing 22 posts - 1 through 22 (of 22 total)
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  • #45609

    AT
    Participant

    How can you really be sure that you have figured out the true root cause and that there isn’t another one below it? Why limit to 5 Whys and not say 6 or 7 ?

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    #149456

    Marlon Brando
    Participant

    It  depends  on  practical experience 5Whys is  fair  enough,you  may  go  above  ,but  it  is  not  necessary?

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    #149460

    AT
    Participant

    Practical experience??? I thought six sigma is teachable science.

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    #149461

    Marlon Brando
    Participant

    5 Whys Was  practised first at  toyota (TPS),it is one of  the  major Kaizen (Lean) tools? 

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    #149462

    Monk
    Participant

    Ramesh,
    The first ‘why’ should be used for the ‘failure mode’ identified and not the problem / symptom.
    Example-
    Problem/Symtom – You are late to reach office every Monday.
    Failure mode- You wake up late in the morning.
    1st why – You were awake till late night the previous night.
    2nd why – You attended a party.
    3rd why – You have it every Sunday.
    4th why – Not reqd.
    In the above example, you have seen that the root cause is ‘you have party on every Sunday’. So solution is to have it on Friday / Saturday evening instead of Sunday.
    Whether you need 5 whys or more will depend on when do you ask the 1st why. Ask the 1st why to the failure mode and you should be able to reach the root cause in next 3-5 steps. Thats what experience says.
    Monk

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    #149463

    Atkins
    Participant

    There is nothing magic about the number 5 in 5-whys.  I’ve worked with situation that were 9-whys.
    Perhaps the best thing about the number 5 is that if you go that many levels, at least you’re not staying at the symptom level.  However, there is still a chance you’re still working at the physical level and not the system (e.g., policy) level.
    You should take it to the level where it makes sense … economically, logically, scope of control, etc.  You can actually take all problems to the level where the root cause is either Adam & Eve, or the Big Bang, or whatever similar theory you ascribe to for the beginning of time/universe.

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    #149464

    Sanjeev Sadavarti
    Member

    Whole concept of reaching to root cause through Why – Why Analysis (or any other tool) depends on two things:
    (1) Each why should focus on causes of effect seen.
    (2) Number of whys are determined based on our capability to ACT e.g. in the example quoted if you are able to sleep on time irrespective of anything..stop there while if you can not change party evening go further…..quality is about action (not analysis – paralysis)
    Most important of all…why – why analysis is a simple tool used for solving simple problems (believe me it depends on experience as well). Some tools which use domain expertise and problem observations as inputs are experience based, while others which are data based are more deterministic. Six Sigma is mix of both types of tools

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    #149467

    Atkins
    Participant

    Good point … good RCA requires both domain knowledge and problem solving knowledge.  In my experience each type of knowledge often should come from different sources.
    A domain expert will jump to conclusions based on their biases, previous experiences, last problem seen, etc.  The problem solving expert will not have sufficient domain expertise, but will focus on ensuring that a good RCA process is used.
    A SSBB should be the RCA expert, and work with project team members who have domain expertise.

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    #149469

    Marlon Brando
    Participant

    RCA stands  for  what? thanks

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    #149471

    Why?
    Member

    Root Cause Analysis!

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    #149473

    Marlon Brando
    Participant

    tHANK yOU

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    #149477

    Hal
    Participant

    “I thought six sigma is teachable science.”
    You must be kidding !!!
    Science doesn’t enter into it … read all the papers on SS … all it’s “facts” are fabrications.

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    #149480

    qualitycolorado
    Participant

    Ramesh,Regarding your note earlier today, where you commented “I thought six sigma is teachable science”.Six Sigma (or Lean, or TQM, or any other improvement methodology) is blend of science and practical experience.Improvement practitioners (Six Sigma, or Lean, or TQM, or any other improvement methodology) are like medical doctors.

    The medical doctor, at a minimum, has to do these things to get certified (licensed):1. go to courses to understand the underlying knowledge of how the human body works (AND pass the exams);2. Follow senior doctors on their rounds, to understand how to apply this knowledge; and3. Practice applying the knowledge under the watchful eye of senior doctors.I would not feel comfortable working with a medical doctor who only went classes and read medical books and journals. I want my doctors to know medicine AND to have learned how to apply it under the watchful eyes of senior doctors.Six sigma practitioners (and Lean Masters, and our other improvement brethren) are the “doctors” in our organizations. I want my improvement “doctors” to:1. go to courses to understand the underlying knowledge of how the “organizational” body works and how to improve it, using Six Sigma, Lean, etc. (AND pass the exams);2. Follow senior Six Sigma practioners on their rounds, to understand how to apply this knowledge — this means being on some projects led by senior BBs or MBBs; and3. Practice applying the knowledge under the watchful eye of senior practitioners — actually do a Project, under the watchful eye of a MBB, or at least a senior BB.If you have read and studied about Six Sigma, Lean, etc., in books, that is only part of what is required. You will also need to practice Six Sigma. If new to Six Sigma, this should be done under the guidance of an experienced practitioner… hope this is helpful ….
    Best regards,QualityColorado

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    #150085

    K.C.SRINATH
    Participant

    Most of the problems when put across Why Why Analysis, you will get the root cause of the problem before addressing the 6th one. Hence it is a std practice to follow Why Why Analysis and my experience also.
    Regds
    K.C.Srinath

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    #150092

    AbetF
    Participant

    Ramesh,
    In Six Sigma, you need to do the 5why’s using the expertise of the CFT in that process. 5Why’s would only give you possible root causes and mind you that the answer of your 1st “Why” is not limited to one answer-you could have as many possible root causes in which you would use for your 2nd level “Why” until you reach the level five “Why.” (some might only be until 3rd level why.)
    1st level       only one  Why1 (the main problem)
    2nd level     Why2a, Why2b, Why2c,….
    3rd level      Why3Aa, Why3Ab,….;Why3Ba, Why3Bb,….
    etc.
    The last answer of your Why’s could reach up to 20 possible root causes or more. You can use C & E matrix to reduce the possible root causes down to the most possible root cause-these are your x’s.
    Now is the time to use the statistical tools, the remaining possible root causes will be evaluated using hypotheses tests or DOE depending on the type of data you can collect.
    As a summary, 5why’s would only help you find the possible root causes, Hypotheses tests and DOE would help you find the root cause which are the significant factors that affect your main problem.
    abetf
     
     

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    #150096

    Deanb
    Participant

    Perhaps the ancient Greek philosophers can help us on this one.According to the teachings of Socrates, if you ask “why” enough times you either will find humorous inconsistency, a mysterious metaphysical reality, or both. Naturally, you want to stop well before you get this far. Hence, you can ask “why” too many times. These wise folks also taught that knowledge is created by the interaction of empiricism (science), common sense (practical experience) and dialog (communication, debate and synergy). If a purpose of Six Sigma is to create knowledge or wisdom, then dialog needs to be added as a third essential.

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    #150114

    MikeHilliard
    Participant

    I’m ever bothered by topics such as this.  We are so focused on buzz that we overlook the simple factors that solve the problems.
    Root cause is a waste of time unless you’re writting a book. Solving problems is the true focus – that’s what we are paid to do…
    If you want a better toolbox, get rid of the fluffy buzz toys and go back to basic problem solving – 5 whys, 6, 7 or 100 – what difference – that’s only a linear story. Focus on solutions and solve those problems.

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    #150137

    melvin
    Participant

    We practice asking “Why?” to the point of getting to an actionable root cause, i.e., an input we can change to get the desired improvement (change in output).  This can mean asking 1, 2, 3, ….7 times.  This works for many problems, because we have never identified and acted on the true root causes, rather we have dealt with addressing the symptoms.  After we get through these problems we may need more complex tools, but let’s save them for when needed.
    It’s an acquired skill, like application of even more well defined statistical tools – you need to work around splitting with answers to Why?, …; with making sure you don;t follow too narrow a trail, etc. 
    Bob

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    #150138

    Why not
    Member

    It is noted after the 7th why the person that is answering your “Y’s” starts becoming annoyed with you.  You can try that with someone

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    #150252

    Mike O’Brien
    Participant

    The ‘true Root cause’ – your Business requirements will determine how far you take any root cause analysis on problem records raised.
    Use tools such as your Service catalaogue and Service Level Agreements to determine how far you take your root cause analysis investigations.
    If your Business stipulate that a true root cause is required for every problem record raised then you need to take the 5 Why’s questioning technique to the nnnth degree.
    That is until you have either identified the ‘true root cause’ or you believe that you and whoever else you have engaged with during the root cause analysis – problem control process – ( identifying the error ) maybe Oracle or other third party vendors for example can confirm that you have exhausted all avenues using other problem solving techniques such as Cause and Effect Analysis, Process Flow charts.
    Remember root cause analysis takes time, costs money and can be very very time consuming and frustrating for all concerned, does your Business requirements make it necessary for you to invest the above indefinately? 
     
     
     

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    #150280

    Mulcahy
    Participant

    Teachable – yes, science – no.

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    #166884

    shyanji
    Member

    HI sanjeev, this is shyamji agrawal – good article on 6 sigma…

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