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Risk Limiting Method (RPL) vs Risk Priority Number (RPN) on D/PFMEA

Discussion in 'APQP and PPAP' started by ncwalker, Mar 20, 2017.

  1. ncwalker

    ncwalker Well-Known Member

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    I am seeing a new thing show up. Instead of calculating RPN as Sev * Occ * Det, there is now an RPL that gives you are result of 1, 2 or 3 (1 being bad, or priority 1 to address). You don't multiply, there's three tables, basically. A Severity x Occurrence table, which gives an intermediate result. And a Severity x Detection table, which gives a second intermediate result. Take these two into a third table and get your RPL level.

    So far I have only seen one OEM mention it.

    Anyone else seeing this? Is it getting traction?

    For what it's worth, it makes a whole lot more sense.
     
  2. johnnymo77

    johnnymo77 Active Member

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    I did see that AIAG has a project to align their FMEA and the VDA FMEA. Maybe its coming from there.
     
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  3. John C. Abnet

    John C. Abnet Well-Known Member

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    This "RPL" term now shows up in the the latest (2023 effective date) GM QSR manual in place of the previous manual's reference to "RPN".
     
  4. Bev D

    Bev D Moderator Staff Member

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    :mad:
    While it make more sense it still doesn’t make sense. It represents a stutter-step away from the jabberwocky of the RPN but does’t go nearly far enough. The core issue here is that the ‘powers that be’ are still terrified of science logic and thinking. They continue to try to reduce beautiful, informative complex knowledge to a single yes/no number that management and other lay people are so fond of.

    Occurence must be measured - and reduced - thru experimentation as must detection’. Reducing these things to a single ordinal character (I refuse to state that the ratings are numbers; they are merely names for particular categorizations) and then multiplying them is still mathematical jabberwocky that obviates thinking and science. This is still statistical alchemy.
     
  5. Andy Nichols

    Andy Nichols Moderator Staff Member

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    This looks like someone’s attempt to mimic the VDA-AIAG “Action Priority” number. Having determined the normal RPN, a table of values is then applied which determines the Action Priority: High, Medium, Low.