Pedro I Espina, NIST

Do you ever wonder if the ACME gadgets that Wile E. Coyote used in his endless pursuit of the Road Runner were traceable? And if they were, to what and how were these gadgets traceable? But more importantly, would the traceability of the ACME gadgets have helped the Coyote catch the Road Runner? Probably, only animation director Chuck Jones knows, but for a metrologist these questions are all valid and should be for providers and consumers alike.

In its International Vocabulary of Basic and General Terms in Metrology (VIM), the International Organization for Standardization (ISO) defines traceability as the “property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties.” In basic terms this means that a claim of traceability is meaningless without three elements: (1) a declaration of the source of traceability (e.g., standards or measurements provided by the Bureau International des Poids et Mesures – BIPM, or the National Institute of Standards and Technology – NIST, or a state office of weights and measures), (2) a full description of the traceability chain from the source to the measurement of interest, and (3) an uncertainty claim with supporting data. The responsibility for providing support for an uncer-tainty claim rests with the entity making the claim (i.e., the provider), but the responsibility for assessing the validity of such a claim rests with the consumer.

For a detailed treatment of the subject and answers to the above questions, please download the complete article by clicking on the link below.