AIAG's MSA Manual 3rd Edition - A Look at K Values - Auditor Questions



MSA 3rd Edition question


I first want to say this is a great forum with a lot of helpful info. I appreciate the service!

The question I have is: We just went through our QS audit and the auditor was questioning what we knew about the K values. with regard to GR&R. In his questioning he asked us why they change in the 3rd edition. I had no reply. Of course he wasn't looking for trouble just trying to see if it made sense to anyone else.

I understand that the K values are based upon the 5.15 @ 99%/ d2. However in the 3rd edition it is now based upon a smaller area under the curve. (Can't remember the exact number right now.) So can anyone tell me what's the deal? It looks like they got a little lenient on us or maybe I am just missing something.

Thanks for any assistance anyone can give.


Atul Khandekar


Welcome to the Cove.

Maybe this little FAQ fro AIAG will help?


  • msa_faq_list.pdf
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Thanks for the assistance, however I am still not convinced with what AIAG is saying. If I put in the new(3rd) edition K values I will get a different GRR. I have verified my excel spreadsheet to the data in the MSA and everything is correct. If I change K values however I get a different GRR%. According to AIAG the K values cancel out. This doesn't appear to be the case. Hmmm...


Are there many changes in the 3rd edition of MSA manual?Do we have to redo all the MSA conducted till now.Sorry Iam curious because I have not yet got the new edition with me.

Atul Khandekar

The third revision is said to be more than a 100 pages longer than the second one.

I don't really think you will have to redo the MSA studies you conducted in the past and I don't think bad gages will become good (or vice versa) with new calculations. ;)

a_amirahmadi - 2002

MSA 3rd Edition

Does any one know where I can get a copy of MSA manual 3rd edition or differences bitween 2rd and 3rd edition?:)


Quite Involved in Discussions
Does anybody know of a training supplier for MSA other than AIAG? Manager thinks AIAG is too expensive.:bonk:
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