The most basic check of a Party’s Uncertainty Analysis whether it covers all source and sink categories.

Your team should also check that each Party has provided detailed information in its NIR on the assumptions, input data, and expert judgments used in preparing their Uncertainty Analysis. This documentation should include the rationales they used in selecting particular assumptions. Again, documentation (transparency) is essential and should be rigorously assessed.

In addition to providing quantitative estimates of uncertainty, each Party should provide an extensive qualitative discussion of the sources of uncertainty in its inventory. This qualitative discussion is important because it is by considering the reasons for the uncertainty in an inventory (not just which parameters are uncertain) that leads to future improvements.

It is important to remember as you and your team are reviewing a Party’s Uncertainty Analysis that you should not overly focus on the technique used for modeling uncertainty. You should instead focus on how the work performed by the Party is “adding value” to the inventory. In other words, you should ask how each Party has used the process of uncertainty analysis to make improvements in the four inventory fundamentals: methods, data, national inventory process (institutional arrangements or system), and transparency (documentation).

As discussed in the previous section on Quality Assurance/Quality Control (QA/QC), a Party’s uncertainty analysis should be integrated with its QA/QC plan.

Lastly, analysts that have conducted comprehensive uncertainty analyses on national inventories of selected Annex I Parties have found that the overall uncertainty in an inventory (depending on the assumptions made) is often dominated by its estimates for N₂O from Agricultural Soils.