Uncertainty Is Not Stated with the Result
So nobody can tell whether a borderline result passed or failed, and the decision gets made by whoever is in the room.
Laboratories & Calibration
Every other system on this site rests on measurements. If the measurement is not defensible, neither is anything built on top of it — which is why calibration findings travel so far up an audit report.
ISO · International
ANSI · United States
FDA · United States
The Shape of It
Two questions decide most of it. Is there an unbroken traceability chain from the instrument on the floor to a national standard? And has anyone quantified how much the measurement system itself contributes to the variation you are attributing to the process?
A gauge R&R answers the second, and surprisingly often changes the answer to the first problem you were investigating — because the variation you were chasing turns out to have been in the gauge.
What Applies
8 Documents an Auditor Is Likely to Open
The working set, not an exhaustive register. Each row prints the body that issues it, so nothing here depends on the color of the rule beside it. Customer-specific requirements sit on top of all of it and are frequently where the real work is.
ISO · Intl
ISO/IEC 17025:2017
Testing and Calibration Laboratories. Competence, impartiality, and consistent operation — the accreditation standard itself.
ISO · Intl
ISO 10012:2026
Measurement Management Systems. Revised in 2026, replacing the 2003 edition. Requirements for the measurement process, not only for the instrument.
ANSI · US
ANSI/NCSL Z540.3
Calibration of Measuring and Test Equipment. Withdrawn by NCSL International in 2020 in favor of ISO/IEC 17025:2017, but still named in older flowdowns, which should be updated.
ISO · Intl
ISO/IEC 17020:2026
Inspection Bodies. Revised in 2026, with a reworked independence model. For work that is inspection rather than test or calibration.
ISO · Intl
ISO 15189
Medical Laboratories. Quality and competence, for laboratories producing clinical results.
FDA · US
21 CFR 58
Good Laboratory Practice. For non-clinical studies supporting a submission.
ISO · Intl
GUM · Guide 98-3
Measurement Uncertainty. JCGM 100:2008, amended in 2026. Stated with the result, or the result is only half reported.
AIAG · US
Gauge R&R
Measurement Systems Analysis. How much of the variation you are seeing belongs to the gauge and to the operator.
Every standard above has a page and a free brief on QES letterhead, with its status as checked on October 24, 2026. Browse Standards & Guidance.
In Practice
Three Things That Usually Go Wrong Here
Not statistics — QES's own reading of where these systems are most often found short, from thirty years of building and auditing them.
Calibration Intervals Were Set Once and Never Reviewed
Twelve months because it has always been twelve months. Actual drift data exists in the certificates and has never been looked at.
Gauge R&R Was Run at Qualification and Never Again
Every operator in the study has since left. The study is evidence about people who no longer work there.
A Real-World Case
A 1.3 Millimeter Error in the Instrument That Checked the Mirror
Hubble’s primary mirror was polished precisely, to the wrong shape, because the test instrument itself was out of position.
1.3 mmlens spacing error in the test instrument, per the 1990 failure board
- What Happened
- Hubble launched on April 24, 1990. Its primary mirror was too flat near the outer edge; NASA says the error was 10 times larger than the specified tolerance.
- What the Investigation Found
- The failure board (the Allen Committee, November 1990) found a lens in the reflective null corrector, the instrument used to test the mirror during polishing, spaced 1.3 mm out of position. Two auxiliary tests had clearly shown the error, and both were discounted at the time as being themselves flawed.
- What It Cost
- Corrective optics were installed by astronauts during the first servicing mission in December 1993.
Sources. NASA — Hubble’s mirror flaw (opens in a new tab); The Hubble Space Telescope Optical Systems Failure Report (Allen Committee, November 1990) (opens in a new tab). A public case, summarized from the official findings and reporting cited; QES was not involved in it. Figures are quoted as published. Checked October 24, 2026.
“Marcia incorporated several evaluation tools and good interview skills. This coupled with her industry and quality background ensured the study was grounded in reality.”
Where to Start
Against the Clause, Not Against a Feeling
A fixed-price gap assessment — two days on your floor and in your files, from $4,200 — produces a clause-by-clause table: what you have, what the standard in your column actually requires, what is missing, and what has to be written — with an owner and a date against each line. You keep the findings whether or not you engage further.
On This Page. The standards listed are the working set an auditor is most likely to open, not an exhaustive register. Dated statements are sourced on the research page. The experience described is drawn from Marcia Weeden's employment record and is available in full on her résumé. Canceled military specifications are marked as canceled where they are still cited in contract flowdowns. Checked October 24, 2026.