The uncertainty budget is simply the way all data is presented to give an overall assessment for the uncertainty of the assay.
Customarily this is presented as a simple table and displays some or all of the following depending on the technique used:
- The Measurand definition
- All significant uncertainty contributors
- The magnitude of the uncertainty of each contributor
- How this was evaluated (i.e. Type A or type B)
- The associated probability distribution of each contributor
- The influence (expressed as a percentage) of each contributor
- How the contributors interact (i.e. are they correlated?)
- Sensitivity coefficients of each contributor
- The technique used to combine the data
- The combined uncertainty
- The expanded uncertainty
Having already identified our contributors, we need to determine what is the most appropriate method at our disposal to assess the assay and determine our uncertainty. It is a discussion of each of these techniques that follows in the coming pages.