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I    Frequently Asked Questions

I.A   Questions about Metrological Traceability in General

I.A.1   What is traceability?

I.A.2   Is it correct to say that measurements or standards are traceable?

I.A.3   Is it correct to say that an organization is traceable?

I.A.4   Who is responsible for supporting claims of traceability?

I.A.5   What do I need to do to support a claim of traceability?

I.A.6   Who is responsible for assessing the validity of claims of traceability?

I.A.7   What should I look for in a valid claim of traceability?

I.B    Questions about Establishing Metrological Traceability

I.B.1   What is involved in establishing metrological traceability?

I.B.2   Who is responsible for establishing the traceability of measurement results?

I.B.3   Does metrological traceability need to be reexamined periodically? What are the criteria for judging the integrity of the metrological traceability chain?

I.B.4   Is a NIST Test Report Number necessary and/or sufficient evidence of traceability?

I.B.5   To establish the traceability of a measurement result for a particular measurand, is it also necessary to establish the traceability of all other values of measured quantities associated with the measurand, especially those that might contribute in a relatively minor way? For example, when making a dimensional measurement, do the measurements of barometric pressure, humidity, and temperature for a dimensional measurement need to be traceable to the International System of Units (SI)?

I.C    Questions about NIST and NIST's Role in Metrological Traceability

I.C.1   What is NIST?

I.C.2   What is NIST's role in metrological traceability?

I.C.3   What is meant by the phrase "traceable to NIST"?

I.C.4   I want my measurement results to be traceable to NIST. What do I have to do?

I.C.5   How does NIST establish the traceability of its own measurement results?

I.C.6   How does NIST support its own claims of traceability?

I.C.7   Does NIST certify the traceability of its own measurement results?

I.C.8   Does NIST certify the traceability of measurement results other than its own?

I.C.9   Given that NIST operates the National Voluntary Laboratory Accreditation Program (NVLAP), does this mean that NIST stands behind claims of traceability made by NVLAP-accredited labs?

I.D    Questions about NIST Products/Services

I.D.1   Does NIST have publications that explain what traceability is and how to achieve it?

I.D.2   What products and services does NIST provide in support of customers seeking to establish traceability?

I.D.3   If I have an instrument or artifact calibrated at NIST, does that make my measurement results traceable to those of NIST?

I.D.4   If I purchase an SRM, does that make my measurement results traceable to NIST?

I.D.5   If I purchase a NIST Traceable Reference Material (NTRM), does that make my measurement results traceable to those of NIST?

I.D.6   NIST data are often used in claims of traceability to NIST. Under what conditions can one consider NIST data to be "specified references"?

I.D.7   Can organizations claim traceability to NIST by having individual instrument components calibrated at NIST? If so, is that the same as sending the entire instrument to NIST for calibration?

I.D.8   How should customers claim traceability to NIST if NIST needs to use two or more of its own standards to calibrate the customer instrument, standard, or artifact?

I.D.9   Can customers claim traceability to NIST for measurement results associated with something that NIST cannot calibrate directly?

I.E    Questions about MRAs and Traceability

I.E.1   What is the CIPM MRA and what does it have to do with traceability?

I.E.2   If a laboratory establishes traceability of its measurement results to standards maintained by National Metrology Institutes (NMIs) that is a signatory to the CIPM MRA, does that mean that that laboratory's measurement results are traceable to standards maintained by other signatory NMIs?

I.E.3   What are laboratory accreditation MRAs and what do they have to do with traceability?

I.E.4   Because NIST's National Voluntary Laboratory Accreditation Program (NVLAP) is a signatory to multiple MRAs with other accreditation bodies, does that mean NIST stands behind claims of traceability made by any laboratory accredited by any other MRA signatory?

II    Examples of NIST Programs in Traceability

II.A    Traceability for Personnel Radiation Dosimetry

II.B    Traceability for Radiopharmaceuticals

II.C    Traceability of Calibration Sources for Radioanalytical Instruments

II.D    Traceability of Commercially Produced Gas Mixture Standards

II.E    Traceability of Ion-Implanted Arsenic in Semiconductor Materials

II.F    Traceability to the International Temperature Scale of 1990 (ITS‑90)

II.G    Traceability to the Coordinated Universal Time Scale

III   Glossary of Terms


IV    References


V     Checklist for Traceability through Calibration