Open Measurement uncertainty from the calibration hub after structured measurements have been saved.
The screenshot shows the explicit blocker displayed when the event has no approved budget revision. Assign the controlled budget through the requirement before starting calculated uncertainty work.
Reference readings and certificate reporting
Record the actual reference reading separately from the nominal target when available. Enter its observed decimal precision, including meaningful trailing zeroes, and use the measurement-set unit. Keep before-adjustment and after-adjustment readings distinct. Certificate uncertainty reporting uses the applicable recorded evidence and coverage factor; a factor alone does not establish a probability or distribution.
Calculated uncertainty
- Confirm the approved uncertainty-budget revision frozen onto the event.
- Confirm the current measurement revision.
- Supply required Type A and Type B component inputs.
- Resolve blocking findings and review warnings.
- Calculate and save the evaluation.
Metra retains the component inputs, distributions, divisors, sensitivity coefficients, degrees of freedom, combined standard uncertainty, coverage factor, and expanded uncertainty for each applicable point and stage.
New calculations use half-even rounding, retaining exact intermediate digits within each decimal operation until its result is rounded. The calculation policy version is retained with the evidence. Earlier saved calculations and issued certificates keep their recorded values; recalculation creates a new evidence revision for review.
Summaries show readable unit symbols and omit redundant decimal padding without changing the stored calculation or its exact structured inputs. Very small nonzero uncertainty remains visible. Member names identify authors and submitters where available; expand record references when tracing a particular revision. Certificate reporting precision still follows the controlled reporting rules.
If measurements are revised, the prior calculation is stale and must be recalculated. The Metra work plan reports this rather than treating old evidence as complete.
Externally reported uncertainty
When the frozen policy is externally_reported, record the supplied uncertainty evidence and its source instead. This policy does not automatically require internal structured measurements.
Keep point work and select reference evidence
Unfinished values, divisors, observations and source links are retained separately for each measurement point and as-found/as-left stage while this page remains open. Calculate and save each point to retain its immutable evidence. Leaving with unfinished input prompts you before discarding it.
For a reference-standard contribution, choose named frozen reference evidence saved for this calibration and measurement set. Metra links its usage identifier, exact usage revision and certificate fingerprint automatically, and pre-fills the stated contribution and coverage factor. You do not need to copy UUIDs or hashes. Save or correct reference-standard usage first if the evidence is missing. Metra checks ownership, coverage and the current immutable revision when saving.
The workspace identifies the actual frozen budget code, name and revision, including an older revision when that is what the event uses. A later approved budget does not replace it. Calculation returns a saved evaluation or an error describing the correction needed; missing standard evidence must be resolved through reference-standard usage before retrying.
For externally reported uncertainty, the work task opens Reported uncertainty evidence. It does not ask you to reproduce the provider's uncertainty through an internal budget.