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Root Causes

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  • #44447

    Sinnicks
    Participant

    I want to validate my root causes I have identified in an Open-Narrow-Close effort.  Can someone tell me which tools or techniques I should be using and in which order I should be using them.  Thanks.

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    #142399

    Rodrigo
    Member

    try to create a Stratified data plot or scatter plots of cause variables Vs the outcome of interest.
    You can also try a quick fix and see the outcome (eg, remove potential cause and see outcome)
    hope it helps 
     

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    #142419

    LBJ
    Participant

    I agree with Rodrigo
    Sometimes the best way to no you have eliminated the root cause is to test it.  I have found that once we get to the implementation there is always some tweaking that must be done.  When a process is dealing with people it is very difficult to “mistake proof” a process. 

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    #142486

    Dr. Mikel Harry
    Member

    Open – Cause and Effect, Cause Screening
    Narrow – Hypothesis Tests, FMEA
    Close – Regression, DOE

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    #142565

    janice gasaway
    Participant

    I have found that identification of root causes begins subjectively with Cause & Effect (matrix and diagram).  I then take the key variables identified in C&E to the FMEA to narrow down to specific causes.  All of these are subjective tools, so next step is make sure you have some data on these causes.  Perform hypothesis testing with the data to show a true link to your process outcome.  Once that is established, you can move forward developing plans for improvement knowing that you have really identified root cause.  Hope this is helpful!

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    #142568

    REM
    Participant

    Root Cause, unless tested, is a subjective means to get to an underlying cause of a failure.  Recall the Fishbone Diagrams, the last thing we did in the analysis was vote or concens on the root cause.  FMEA should be the tool to identify the basic cause or first level casue, then further analysis of the first level cause may result in identifying the root cause

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    #142570

    Jim Wasiloff
    Participant

    You may wish to consider the problem solving methodology of Shainin Red X in identification of root cause.  The Shainin method involves a highly structured statistical strategy of systematically studying contrasts between “Best of the Best”  and “Worst of the Worst” from the tails of the distribution of systems, sub-sytems or components, converging on root cause and statistical confirmation of achieving irreversible corrective action.  The process culminates in the proven ability to turn on and off the “Red X” and implementation of error proofing. 

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    #142609

    Jonathon Andell
    Participant

    Hello Mike! How have you been doing?

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    #142640

    Benjamin Sagalovsky
    Participant

    Shouldn’t we add Value Stream Mapping to that list of ‘Open’ phase tools? We sometimes struggle on how to incorporate Lean tools, but aren’t they just a means for, first, uncovering problem areas (possible causes) and, then, suggesting solutions  — which we, as Six Sigma practitioners, should validate from historical or, even better, experimental data?
    Sorry for opening this sideline, I saw the list of tools and couldn’t help it!

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