Notes

NOTE 1 For this definition, a 'reference' can be a definition of a measurement unit through its practical realization, or a measurement procedure including the measurement unit for a non-ordinal quantity, or a measurement standard.

NOTE 2 Metrological traceability requires an established calibration hierarchy.

NOTE 3 Specification of the reference must include the time at which this reference was used in establishing the calibration hierarchy, along with any other relevant metrological information about the reference, such as when the first calibration in the calibration hierarchy was performed.

NOTE 4 For measurements with more than one input quantity in the measurement model, each of the input quantity values should itself be metrologically traceable and the calibration hierarchy involved may form a branched structure or a network. The effort involved in establishing metrological traceability for each input quantity value should be commensurate with its relative contribution to the measurement result.

NOTE 5 Metrological traceability of a measurement result does not ensure that the measurement uncertainty is adequate for a given purpose or that there is an absence of mistakes.

NOTE 6 A comparison between two measurement standards may be viewed as a calibration if the comparison is used to check and, if necessary, correct the quantity value and measurement uncertainty attributed to one of the measurement standards.

NOTE 7 The ILAC considers the elements for confirming metrological traceability to be an unbroken metrological traceability chain to an international measurement standard or a national measurement standard, a documented measurement uncertainty, a documented measurement procedure, accredited technical competence, metrological traceability to the SI, and calibration intervals (see ILAC P-10:2002).

NOTE 8 The abbreviated term “traceability” is sometimes used to mean 'metrological traceability' as well as other concepts, such as 'sample traceability' or 'document traceability' or 'instrument traceability' or 'material traceability', where the history (“trace”) of an item is meant. Therefore, the full term of “metrological traceability” is preferred if there is any risk of confusion.

1 Quantities and units

• 1.1 quantity
• 1.2 kind of quantity
• 1.3 system of quantities
• 1.4 base quantity
• 1.5 derived quantity
• 1.6 International System of Quantities
• 1.7 quantity dimension
• 1.8 quantity of dimension one
• 1.9 measurement unit
• 1.10 base unit
• 1.11 derived unit
• 1.12 coherent derived unit
• 1.13 system of units
• 1.14 coherent system of units
• 1.15 off-system measurement unit
• 1.16 International System of Units
• 1.17 multiple of a unit
• 1.18 submultiple of a unit
• 1.19 quantity value
• 1.20 numerical quantity value
• 1.21 quantity calculus
• 1.22 quantity equation
• 1.23 unit equation
• 1.24 conversion factor between units
• 1.25 numerical value equation
• 1.26 ordinal quantity
• 1.27 quantity-value scale
• 1.28 ordinal quantity-value scale
• 1.29 conventional reference scale
• 1.30 nominal property

2 Measurement

• 2.1 measurement
• 2.2 metrology
• 2.3 measurand
• 2.4 measurement principle
• 2.5 measurement method
• 2.6 measurement procedure
• 2.7 reference measurement procedure
• 2.8 primary reference measurement procedure
• 2.9 measurement result
• 2.10 measured quantity value
• 2.11 true quantity value
• 2.12 conventional quantity value
• 2.13 measurement accuracy
• 2.14 measurement trueness
• 2.15 measurement precision
• 2.16 measurement error
• 2.17 systematic measurement error
• 2.18 measurement bias
• 2.19 random measurement error
• 2.20 repeatability condition of measurement
• 2.21 measurement repeatability
• 2.22 intermediate precision condition of measurement
• 2.23 intermediate measurement precision
• 2.24 reproducibility condition of measurement
• 2.25 measurement reproducibility
• 2.26 measurement uncertainty
• 2.27 definitional uncertainty
• 2.28 Type A evaluation of measurement uncertainty
• 2.29 Type B evaluation of measurement uncertainty
• 2.30 standard measurement uncertainty
• 2.31 combined standard measurement uncertainty
• 2.32 relative standard measurement uncertainty
• 2.33 uncertainty budget
• 2.34 target measurement uncertainty
• 2.35 expanded measurement uncertainty
• 2.36 coverage interval
• 2.37 coverage probability
• 2.38 coverage factor
• 2.39 calibration
• 2.40 calibration hierarchy
• 2.41 metrological traceability
• 2.42 metrological traceability chain
• 2.43 metrological traceability to a measurement unit
• 2.44 verification
• 2.45 validation
• 2.46 metrological comparability of measurement results
• 2.47 metrological compatibility of measurement results
• 2.48 measurement model
• 2.49 measurement function
• 2.50 input quantity in a measurement model
• 2.51 output quantity in a measurement model
• 2.52 influence quantity
• 2.53 correction

3 Devices for measurement

• 3.1 measuring instrument
• 3.2 measuring system
• 3.3 indicating measuring instrument
• 3.4 displaying measuring instrument
• 3.5 scale of a displaying measuring instrument
• 3.6 material measure
• 3.7 measuring transducer
• 3.8 sensor
• 3.9 detector
• 3.10 measuring chain
• 3.11 adjustment of a measuring system
• 3.12 zero adjustment of a measuring system

4 Properties of measuring devices

• 4.1 indication
• 4.2 blank indication
• 4.3 indication interval
• 4.4 nominal indication interval
• 4.5 range of a nominal indication interval
• 4.6 nominal quantity value
• 4.7 measuring interval
• 4.8 steady-state operating condition
• 4.9 rated operating condition
• 4.10 limiting operating condition
• 4.11 reference operating condition
• 4.12 sensitivity of a measuring system
• 4.13 selectivity of a measuring system
• 4.14 resolution
• 4.15 resolution of a displaying device
• 4.16 discrimination threshold
• 4.17 dead band
• 4.18 detection limit
• 4.19 stability of a measuring instrument
• 4.20 instrumental bias
• 4.21 instrumental drift
• 4.22 variation due to an influence quantity
• 4.23 step response time
• 4.24 instrumental measurement uncertainty
• 4.25 accuracy class
• 4.26 maximum permissible measurement error
• 4.27 datum measurement error
• 4.28 zero error
• 4.29 null measurement uncertainty
• 4.30 calibration diagram
• 4.31 calibration curve

5 Measurement standards (Etalons)

• 5.1 measurement standard
• 5.2 international measurement standard
• 5.3 national measurement standard
• 5.4 primary measurement standard
• 5.5 secondary measurement standard
• 5.6 reference measurement standard
• 5.7 working measurement standard
• 5.8 travelling measurement standard
• 5.9 transfer measurement device
• 5.10 intrinsic measurement standard
• 5.11 conservation of a measurement standard
• 5.12 calibrator
• 5.13 reference material
• 5.14 certified reference material
• 5.15 commutability of a reference material
• 5.16 reference data
• 5.17 standard reference data
• 5.18 reference quantity value