Author an uncertainty budget

For the meaning of uncertainty, components and coverage factors, start with Measurement uncertainty.

An uncertainty budget defines how Metra combines controlled Type A and Type B contributions. The budget is the controlled identity; its revision contains the calculation assumptions. It is separate from the observations and measurements produced during one calibration.

You can author and approve a budget before creating a procedure or requirement template. Define the measurement model and applicable units first; actual observations and reference-standard evidence are supplied during calibration work. Arrange an independent authorised reviewer for approval, then select the approved revision wherever calculated uncertainty is required.

1. Open Calibration, then Uncertainty budgets.
2. Select Create uncertainty budget.
3. Enter the controlled code and title, then define the initial revision's quantity, exact unit code, applicable range, purpose, scope, dates, and change summary.
4. Add ordered components for the reference standard, resolution, stability, repeatability, interpolation, or another supported source.
5. Select the evaluation type and distribution for every component.
6. Enter controlled magnitudes only when the value is part of the definition. Reference-standard values and repeated readings are resolved during work.
7. Enter sensitivity coefficients and degrees of freedom where applicable.
8. Save the budget and its initial draft revision.

The initial revision uses the controlled fixed coverage policy k = 2. Metra stores decimal strings exactly and performs official arithmetic on the service. The website formats applicable results to three decimal places without reducing retained precision.

Only draft revisions can enter the submit-and-approve lifecycle. The draft author can Edit draft with a reason. Use Create replacement draft after an earlier revision has been approved, rejected or withdrawn. See Uncertainty-budget revisions for correction and supersession.

This release does not accept arbitrary formulas, implicit unit conversion, correlated components, covariance, interpolation models, guard banding, Monte Carlo models, or variable coverage factors.

Next: Review and approve an uncertainty budget.