Traceability aka “NIST Traceable”

• Definition: An unbroken chain of comparisons going back to documented references acceptable to the parties, usually a national or international standard held at or with governing body (i.e. NIST)

Considerations:

• One can claim traceability without any certification or third party accreditation

• If one wants to eliminate unfounded claims and faulty testing procedures, they should seek calibration testing from an accredited laboratory. (See Accreditation)

• Benefits (Why Bother?):

It establishes some degree of credibility when you can’t track down “lineage” on your own. The value of that credibility can vary as traceability often feels more authoritative than it might actually be as there really aren’t firm rules for claiming traceability. One might have almost no competence at testing devices thereby compromising results while still comparing DUTs to traceable standards. A flawed test can’t be ruled out when one simply claims traceability. 

• Method (How to Do It Well):

Measurement uncertainty: The uncertainty of measurement for each step in the traceability chain must be calculated or estimated according to agreed methods and must be stated so that an overall uncertainty for the whole chain may be calculated or estimated. (This is represented as a plus sign over a minus sign in front of a number (e.g. ± 0.7°F.)

Documentation: Each step in the chain must be performed according to documented and generally acknowledged procedures, and the results must be recorded.

Competence:  The laboratories or bodies performing one or more steps in the chain must supply evidence for their technical competence.

• Recommended Tools

Many of our models include a traceable calibration certificate. Some need something more comprehensive or custom than that and for those reasons, we offer in-house calibration services in our accredited calibration lab.