The methodology for conducting a key category analysis, as defined by the IPCC Good Practice Guidance (IPCC 2000) and Good Practice Guidance for LULUCF (IPCC 2003), includes: · 

• Tier 1 approach (including both level and trend assessments);
  
  
• Tier 2 approach (including both level and trend assessments, and incorporating uncertainty analysis); and
  
  
• Qualitative approach.

Click on any of the methods in the Figure to know more about it.

One of the most important factors in preparing a key category analysis is how categories are grouped or disaggregated. Obviously, the size (i.e., level) and trend in a category can be significantly influenced by what sub-categories are included or excluded from the category. Therefore, the IPCC Good Practice Guidance provides a default categorization for the purpose of identifying key categories. However, Parties are also allowed flexibility in their determination of key categories.

As a reviewer you will have a Tier 1 Key Category analysis for each Party that was performed by Secretariat based on CRF data in addition to any analysis prepared by the Parties.