Dictionary · Quality & Accreditation
Decision rule
A documented rule describing how measurement uncertainty is accounted for when stating conformity with a specified requirement — required by ISO/IEC 17025:2017 when a laboratory reports pass/fail.
Related terms
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Calibration and measurement capability (CMC)
The smallest uncertainty of measurement a laboratory can achieve within its accredited scope when performing more or less routine calibrations of nearly ideal devices — the uncertainty published in its scope of accreditation.
ILAC-P14:09/2020
Accreditation
Third-party attestation, by an authoritative body, of a conformity assessment body's competence to carry out specific tasks — for laboratories, against ISO/IEC 17025, by bodies operating under ISO/IEC 17011.
ISO/IEC 17011:2017
Test uncertainty ratio (TUR)
The ratio of the tolerance of the unit under test to the expanded uncertainty of the measurement process used to test it. A 4:1 TUR is the traditional benchmark; lower ratios call for guard banding or risk analysis (ANSI/NCSL Z540.3).
ANSI/NCSL Z540.3
Check standard
A stable artifact or instrument measured regularly within a measurement assurance program; its control chart reveals drift, shifts, or loss of statistical control of the process.
NIST SOP 30 / GLP 1
Validation
Verification where the specified requirements are shown to be adequate for an intended use — demonstrating a procedure is fit for its purpose.
VIM (JCGM 200:2012) 2.45
Proficiency testing
Evaluation of participant performance against pre-established criteria by means of interlaboratory comparisons — an ISO/IEC 17025 requirement for demonstrating ongoing competence.
ISO/IEC 17043:2023