Calibration Laboratories Editing and Proofreading Services

A calibration laboratory issues a certificate for a pressure transducer reading "as found: within tolerance." The instrument goes back into service on a production line. Eight months later a batch fails and the investigation works backwards to that certificate, asking what the actual as-found readings were, what uncertainty the laboratory claimed, and whether the transducer was within tolerance by a comfortable margin or by less than the measurement uncertainty itself. The certificate answers none of it, and the client cannot establish whether the instrument was drifting the whole time.

We edit what calibration laboratories produce — calibration certificates and reports of measurement, uncertainty budgets and traceability statements, scope of accreditation documents, calibration procedures and work instructions, quality manuals and management system documentation, proficiency testing and interlaboratory comparison reports, equipment records and intermediate check documentation, client quotations describing scope and capability, and non-conforming work and corrective action records. Our editors work on the certificate a failure investigation reads backwards from.

The calibration certificate is the only permanent record of an instrument's condition on a given day, and its failure is a pass statement standing where the measured values should be. We work through these so the as-found readings are reported as actual measured values at each calibration point, before any adjustment, since a within-tolerance statement conceals whether the instrument was at the edge of its limit or comfortably inside it, and a drift investigation needs the number rather than the verdict; so as-found and as-left are reported separately whenever an adjustment was made, given that a certificate showing only the post-adjustment condition hides the fact that anything was wrong; so the measurement uncertainty is stated for each result with its coverage factor and confidence level, because a result within tolerance by less than the uncertainty has not actually been shown to be in tolerance at all; so the traceability chain is identified by the specific reference standard used, its own certificate number and calibration date, rather than a general assertion that measurements are traceable to national standards; and so any point where the instrument was not tested is stated as untested, since a certificate silent on the upper range is routinely read as covering it. Certificates written this way still answer questions eight months later.

Everything you send is treated in confidence, including client data, measurement results and laboratory documentation. We are editors rather than metrologists, calibration technicians or accreditation assessors, and we offer no view on measurement results, uncertainty calculations or technical conformity. What we can do is make sure the certificate records the measurement rather than the verdict.