Measurement System Analysis

ISO/IEC 17025:2017 General requirements for the competence of testing and calibration laboratories


Is there ever an exception to the rule about needing full Measurement System Analysis for any instrument placed in the Evaluation / Measurement Technique column on the Control Plan?  If an instrument is listed on the control plan, does it HAVE to have GRRs done, in addition to having to prove stability?  Please base off of ISO 9001 and TS 16949 requirements, and if there is a difference between them for this requirement.   


Thank you for this interesting question. Clause 7.6 of ISO 9001: 2008 makes most of this fairly clear. Any monitoring and measuring equipment used to verify conformity of product must “be calibrated or verified, or both, at specified intervals, or prior to use. . .” Notice I made ‘at specified intervals’ bold. This is just to bring to light the importance of calibration cycles. You/your organization can determine what those cycles will be based on the stability of the measuring tool, frequency of use, working conditions, etc. For example, if you were using a micrometer to check close tolerance parts and, you found it a good process to measure the parts frequently, this would be a contributing factor to the decision process. Then, if the working conditions included a lot of cutting fluids or perhaps a good deal of metal dust, another factor is added to the decision process. What I am driving at is this; once you have determined that the product conformity which you are checking is good and/or consistent and that your sample frequency is satisfactory, you would have no definite requirement for GRR’s on the measuring equipment. The calibrations and or verifications you do must be with equipment which is traceable to international or national measurement standards. If you use working standards as gages to check measuring equipment throughout production and those standards are traceable, then you are doing fine. The processes you use to verify the tools and any in-process measuring practices should be documented in Work Instructions or even with the use of photographs or flow charts.

In the second part of your question, you ask if there is a difference between 9001 and TS 16949. I reference section 7.6.1 of TS 16949. Here it is put straight forward:

7.6.1  Measurement System Analysis 

Conduct statistical studies to analyze variation present in the results of each type of MMD that is referenced in the Control Plan.

Use analytical methods & acceptance criteria that: 

Conform to methods and criteria in customer reference (MSA) manuals Or use other methods, if approved by the customer 

This is an automotive sector specific QMS standard. Herein it is necessary to consider safety and liability in everything you do. So, Gage R&R’s are a common practice. Nonetheless, the necessity for these is dictated by individual processes. Some may need them, some may not.

So, if an instrument is listed on YOUR control plan, GRR’s will become a requirement based on all the criteria I’ve noted above. A gage which has proven stability is most often safe from that requirement under 9001 but TS16949 has more extensive requirements.

Bud Salsbury, CQT, CQI

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TS 16949 Calibration Management

Automotive inspection, TS 16949, IATF 16949

Q: Under the standard ISO/TS 16949:2009 Quality management systems – Particular requirements for the application of ISO 9001:2008 for automotive production and relevant service part organizations — is it acceptable to allow an instrument user to request a calibration extension under certain circumstances?

Here are just a couple of examples:

The user is in the middle of a test that they don’t want to disrupt until completed.
Equipment is installed on a test vehicle that is at a remote location and is not readily available.

I should note we are an automotive supplier engineering facility doing advanced product development.

A: Here is my usual advice about calibrations:

1. The calibration frequency is both a matter of use and criticality of measures. Instrument companies err on the side of frequent recalibrations.

2. As with most standards based on ISO 9001:2008, the calibration frequency is an internal company decision as the requirement is:

•    Process for calibration management
— Records need to show (7.6.2):
> Equipment identification, including the measurement standard against which the equipment is calibrated
> Revisions following engineering changes
> Any out-of-specification readings as received for calibration/verification
> An assessment of the impact of out-of-specification condition
> Statements of conformance to specification after calibration/verification
>  Notification to the customer if suspect product or material has   been shipped

Therefore, it is the supplier who determines the frequency of the calibration, as well as the standard to which they are using. If the supplier sets a frequency schedule they should follow it unless they get a concession from their customer.

I have done a large calibration study where an engine plant did the statistical analysis, which saved them millions of dollars to set optimal gauging schedules for an engine plant. I recommend that such a study be conducted by this company as soon as possible.

Ron Berglund
Voting member of the U.S. TAG to ISO/TC 176
ASQ Fellow
Canton, MI

For more on this topic, please visit ASQ’s website.