quantity that, in a direct measurement, does not affect the quantity that is actually measured, but affects the relation between the indication and the measurement result

EXAMPLE 1 Frequency in the direct measurement with an ammeter of the constant amplitude of an alternating current.

EXAMPLE 2 Amount-of-substance concentration of bilirubin in a direct measurement of haemoglobin amount-of-substance concentration in human blood plasma.

EXAMPLE 3 Temperature of a micrometer used for measuring the length of a rod, but not the temperature of the rod itself which can enter into the definition of the measurand.

EXAMPLE 4 Background pressure in the ion source of a mass spectrometer during a measurement of amount-of-substance fraction.

NOTE 1 An indirect measurement involves a combination of direct measurements, each of which may be affected by influence quantities.

NOTE 2 In the GUM, the concept 'influence quantity' is defined as in the second edition of the VIM, covering not only the quantities affecting the measuring system, as in the definition above, but also those quantities that affect the quantities actually measured. Also, in the GUM this concept is not restricted to direct measurements.

- 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

- 2.1 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

- 3.1 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

- 4.1 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

- 5.1 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