quantity that must be measured, or a quantity, the value of which can be otherwise obtained, in order to calculate a measured quantity value of a measurand
EXAMPLE When the length of a steel rod at a specified temperature is the measurand, the actual temperature, the length at that actual temperature, and the linear thermal expansion coefficient of the rod are input quantities in a measurement model.
NOTE 1 An input quantity in a measurement model is often an output quantity of a measuring system.
NOTE 2 Indications, corrections and influence quantities can be input quantities in a measurement model.
ANNOTATION (informative) [2 December 2014] Here "measured quantity value" can be replaced by "measured value" without ambiguity: "quantity that must be measured, or a quantity, the value of which can be otherwise obtained, in order to calculate a measured value of a measurand".