Measurement uncertainty

Measurement uncertainty quantifies the dispersion of values that could reasonably be attributed to a measured quantity. It accompanies a measurement result rather than correcting it or indicating a mistake.

GUM framework: The international framework for evaluating and expressing uncertainty in measurement. It provides the standard vocabulary and procedures for turning uncertainty sources into a reported result.
Measurement: A process of experimentally obtaining one or more quantity values that can reasonably be attributed to a quantity. Uncertainty qualifies the value produced by this process.
Metrology: The science of measurement, including its theory, methods, and practical implementation. Metrology develops the methods used to evaluate and communicate uncertainty.
Systematic error: A component of measurement error that remains constant or varies predictably across repeated measurements. A known systematic effect may be corrected, while uncertainty describes doubt remaining in the result.
Guide to the Expression of Uncertainty in Measurement: An international guide, first published in 1993, establishing principles for evaluating and expressing measurement uncertainty. The guide formalized the framework commonly used to report uncertainty.
Standard uncertainty: Uncertainty expressed as a standard deviation. It puts uncertainty contributions on a common scale for calculation.
Measurand: The quantity intended to be measured. Uncertainty is meaningful only in relation to a clearly specified target quantity.
Calibration: An operation establishing a relation between instrument indications and reference quantity values with uncertainties. Calibration results contribute uncertainty to subsequent measurements.
Random error: A component of measurement error that varies unpredictably across repeated measurements. Random variation is one source of uncertainty, not the whole of it.
International Vocabulary of Metrology: An international vocabulary defining concepts used in metrology. Its definitions distinguish uncertainty from error, precision, and related measurement terms.

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