International vocabulary of metrology – Basic and general concepts and associated terms (I)
Bureau International des Poids et Mesures
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measurement accuracy (== accuracy of measurement)
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closeness of agreement between a measured quantity value and a true quantity value of a measurand
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www.bipm.org/en/publications/guides/vim.html
measured quantity value (= value of a measured quantity = measured value)
quantity value representing a measurement result
true quantity value (== true value of a quantity == true value)
quantity value consistent with the definition of a quantity
measurement precision (== precision)
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closeness of agreement between … measured quantity values obtained by replicate measurements on the
same or similar objects under specified conditions
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The ‘specified conditions’ can be, for example, repeatability conditions of measurement , …, or reproducibility
conditions of measurement
repeatability condition … same measurement procedure, same operators, same measuring system, same
operating conditions and same location, and replicate measurements on the same or similar objects over a short
period of time
reproducibility condition .. that includes different locations, operators, measuring systems, and replicate
measurements on the same or similar objects
Measurement precision is usually expressed numerically by measures of imprecision, such as standard deviation,
variance, or coefficient of variation under the specified conditions of measurement.
Measurement precision is used to define measurement repeatability , …, and measurement reproducibility.
Sometimes “measurement precision” is erroneously used to mean measurement accuracy .
Emittance WG, B.Dehning
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International vocabulary of metrology – Basic and general concepts and associated terms (II)
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measurement error (== of measurement == error)
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measured quantity value minus a reference quantity value
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systematic measurement error (== systematic error of measurement == systematic error)
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component of measurement error that in replicate measurements remains constant or varies in a predictable
manner
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A reference quantity value for a systematic measurement error is a true quantity value , or a measured quantity value of a
measurement standard of negligible measurement uncertainty , or a conventional quantity value.
Systematic measurement error, and its causes, can be known or unknown. A correction can be applied to compensate for a
known systematic measurement error.
Systematic measurement error equals measurement error minus random measurement error.
random measurement error (== random error of measurement == random error)
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component of measurement error that in replicate measurements varies in an unpredictable manner
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reference quantity value (== reference value) quantity value used as a basis for comparison with values of quantities
of the same kind
A reference quantity value for a random measurement error is the average that would ensue from an infinite number of replicate
measurements of the same measurand.
Random measurement errors of a set of replicate measurements form a distribution that can be summarized by its expectation,
which is generally assumed to be zero, and its variance.
Random measurement error equals measurement error minus systematic measurement error.
measurement uncertainty (== uncertainty of measurement == uncertainty)
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non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand,
based on the information used
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Emittance WG, B.Dehning
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