Five Common Mistakes with Gage R&R Studies

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Thanks so much for reading our publication. We hope you find it informative and useful. Happy charting and may the data always support your position.


Dr. Bill McNeese
BPI Consulting, LLC

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Measurement Systems Analysis/Gage R&R

Comments (10)

  • Jose ChvaicerJanuary 2, 2020 Reply

    Figure 4 expalnation is directing to Figure 5. Is this a typo? 

    • billJanuary 2, 2020 Reply

      Yes it is a type and has been corrected.  Thanks!

  • JordanApril 26, 2021 Reply

    How to check if the data is being manufactured? I mean, the result is too good to be true.

    • billApril 27, 2021 Reply

      There is no set way I don't think – one thing that people sometimes do is to include a part that is way out of specs in the analysis – this makes the results look better than they many actually be.

  • MaryazmOctober 30, 2021 Reply

    If the answer of our Gage R&R  was 0.02 and it of course acceptable.  We produce 3000 pieces in a day .Does it mean that it's ok to have 60 pieces of not ok products???Can you help.Thanks 

    • billOctober 31, 2021 Reply

      That is not what 0.02 GAge R&R means.  If it is based on variance, it means that 2% of the total variance in product measurements are due to the measurement s ystem.  

  • Gustavo CastilloMarch 28, 2022 Reply

    Should I use the same dimension for allt the samples? Or is it ok to use different dimensions and pieces for each 30 samples?Say I use gage blocks from 5mm, 6mm, 7mm up to 30 pieces?

    • billMarch 30, 2022 Reply

      What do you want to show?  I wold probably use the same dimension each time.

  • Peter BrownMarch 29, 2022 Reply

    I find the article very helpful. I am just trying to find my way in the GRR ‘jungle’. Now I have a question that I have not seen addressed anywhere. What is the appropriate type, or is there a specific type of GRR study for a case whereby one operator cannot measure the same piece more than once (because it cannot be ensured that the operator cannot identify the piece), but different operators can measure the same piece (once)? So, for example, 5 operators measure 5 pieces once only, 25 measurements in total. Thank you.

    • billMarch 30, 2022 Reply

      Hello Peter, I have not run across the situation you describe.  I am not sure where this would occur.

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