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Out of Control versus In Control Tools

Six Sigma – iSixSigma Forums Old Forums General Out of Control versus In Control Tools

Viewing 6 posts - 1 through 6 (of 6 total)
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  • #46993

    Alvarez
    Participant

    Why is it that Pareto, Fishbone, and Countermeasures tools are not used when a process is out of control?

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    #156088

    Chris Seider
    Participant

    Remember when a process is out of control, immediate actions should be taken to get the process in control.  Those countermeasures must have been predetermined ahead of time….
     
    However, pareto, fishbone, and other tools are to be used when enough data is gathered to see frequeny of causes for out of control conditions.  This further reduces the long term variation over time…

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    #156089

    BritW
    Participant

    You can use pareto and fishbone when a process is out of control.  They help you identify the special causes, as do scatter plots and other types of visual charts.

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    #156090

    Caveat
    Participant

    One caveat on the use of pareto charts in out of control conditions: The pareto chart is often affected when used for an out-of-control process in that the bars tend to become “flat” and “unstaggered”.

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    #156091

    CT
    Participant

    How do you know the process is out of control?

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    #156092

    Alvarez
    Participant

    First thanks for the reply. When you say countermeasures must have been determined ahead of time – do you mean that there “usually” is a strategy in place such that “If x occurs” then we will “do y”? But doesn’t this presume prior knowledge of cause and effect?So if the later is true then are you saying (?)special causes are known [in some cases…they’ve occurred before], and they can occur again…and if they do…?This explain why you wouldn’t need fishbone and countermeasures. But if you never seen the problem before I suspect you would use them or are the special causes that obvious?The reason I asked the question in the first place is because every source I’ve read said to use these tools only after the process is in control. I think I see why now. Thank you very much.

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Viewing 6 posts - 1 through 6 (of 6 total)

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