What does a certificate of calibration issued by an NMI indicate about traceability?

A certificate of calibration issued by a National Metrology Institute (NMI) is considered a critical document in the field of metrology, particularly in establishing traceability. When a calibration certificate comes from an NMI, it signifies that the measurements made are traceable to national or international standards. This traceability is fundamental in various industries as it assures that the calibration process adheres to high standards of accuracy and reliability.

The certificate indicates that the equipment was calibrated using recognized standards, and it provides a clear path back to those standards. This means that the results can be confidently used in quality assurance processes without needing to present further documentation to prove traceability. This is why this choice is regarded as the correct answer, highlighting the inherent reliability and recognition of the calibration by an authoritative body.

The other choices present different implications that do not apply when a certificate is issued by an NMI, such as the need for additional documentation, invalid status for quality assurance, or the requirement for regular validation, which not only complicates the matter unnecessarily but also misrepresents the strength of NMI's certifications in establishing traceability.