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4.11.4 MSA is R&R Enough? Linearity, bias, stability necessary as well?



During our last surveillance audit, we were told by the auditor that just doing gage R&R is not enugh to satisfy this requirment. He said that to pass this part of the audit next time, we would have to do more. The requirement says "Appropriate statistical studies...." In my applications, I feel R&R alone is appropriate.
two questions:
1)Has anyone else heard of this requirement?
2)Who defines what is "appropriate" or not?


Captain Nice
Staff member
They want you to address MSA, not just the R&R part. Linearity, bias, stability, etc.

Nope - R&R used to be 'enough'. That 'changed' several years ago.

Dan Larsen

A question here...can the linearity, bias, stability issue for existing systems be answered with manufacturer statements for the existing gauging systems? Procedures would be required to evaluate these characteristics for any new systems put in place.


Captain Nice
Staff member
I'm going to start out by referring you to It's a bit of a read but all in all gives you some idea of the history and debate involved here.

As far as I understand it (I haven't been through a QS implementation in over a year and things do change) NO - You can take that as a 'starting point' and you can use their uncertainty statement for use in your uncertainty calculations, but that's not what is going on here. They want you to explain your system and show what you're tracking 'statistically'. I used to argue that about all that was necessary was R&R but that changed.

The latest is:

->QS 9000 if implemented as per requirement does in fact
->require a MSA on all of your measurement devices denoted
->on the Control plan. The definition of MSA is Gauge
->Repeatability & Reproducibility, Stability, Linearity and
->Bias. All five studies are required on each type of
->measurement device.
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