Maximum permissible error and accuracy class
A specification limit is not an uncertainty estimate.
Key knowledge
A maximum permissible measurement error is an extreme error value permitted by specifications or regulations for a measurement, instrument or system. An accuracy class groups instruments or systems meeting stated metrological requirements intended to keep errors or instrumental uncertainties within specified limits under stated conditions. Neither label automatically supplies the standard uncertainty of a particular measurement result.
Conditions and scope
- Use the actual applicable specification and its conditions; instrument error limits differ from product tolerance limits.
- Converting a bound to an uncertainty requires an explicitly justified model and other components. “Accuracy” as a qualitative VIM concept is not a numerical standard uncertainty.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
- International Vocabulary of Metrology (VIM3)Joint Committee for Guides in Metrology (JCGM)Reference guideVIM3, entry 4.25VIM3, entry 4.26
Evidence and review
Read VIM4.25 accuracy-class definition/note and4.26 maximum-permissible-error definition/note. Keep specification limits distinct from result uncertainty and avoid an unsupported bound-to-standard-deviation formula.
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Entry details
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- foundation-measurement-permissible-error-class
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- foundations-refresh.1
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- Foundational reference additions