Metrological traceability, property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty.
Metrological traceability is essential for meaningful measurement results as it helps demonstrate that such comparisons are scientifically valid. It is meaningful to compare the length of a football field with the distance between street lights as long as they are both expressed in metres – the same unit of measurement. However, just because results are metrologically traceable does not mean they are fit for purpose as it does not ensure that the measurement uncertainty is adequate. For example, the measurement result obtained when weighing a certain mass of sodium chloride using a calibrated technical (2-figure) balance is metrologically traceable to the kilogram. This may be fit for purpose for preparing reagents such as buffers but may not be sufficiently accurate for the preparation of calibration solutions for the determination of low concentrations of sodium in water. In addition, to ensure that measurement results are fit for purpose, the measurement procedures used must be validated and adequate on-going quality control procedures must be in place.
Metrological traceability: Terminology in Analytica Measurement Introduction to VIM 3
