Inside SOP 1: what belongs on a calibration certificate

A calibration certificate is a legal and technical document pretending to be a form. SOP 1 — the very first procedure in the NIST series, in full in the library with its sample appendices — is the anatomy lesson: what must appear, where, and why.

The skeleton matches ISO/IEC 17025 §7.8: unambiguous identification of the item and the standards used (with THEIR traceability), the results with units, the measurement uncertainty with coverage information, environmental conditions where relevant, the procedure used, and the authorizing signature. SOP 1's contribution is state-laboratory practicality — page-by-page templates and the appendix examples showing compliant certificates for common work.

The reading habit it builds transfers to purchasing: the scope-of-accreditation article earlier this month covered choosing a lab; SOP 1 is the checklist for judging the paper that comes back. A certificate missing uncertainty, standards identification, or a decision rule beside its pass/fail claim is a receipt, not evidence.