According to decisions in particular, decisions 2/CP.1, 9/CP.2, 6/CP.3 11/CP.4, 33/CP.7, 7/CP.11, 9/CP.16,  22/CMP.1 and 26/CMP.1 each national communication (NC) of an Annex I Party is subject to an "in-depth" review.

The in-depth review is conducted by an international team of experts, coordinated by the UNFCCC secretariat. The review of each NC typically involves a desk-based study and an in-country visit, and aims to provide a comprehensive, technical assessment of a Party's implementation of its commitments. The in-depth review results in an in-depth review report, which typically expands on and updates the NC. The in-depth review reports aim to facilitate the work of the COP in assessing the implementation of commitments by Annex I Parties. The reports also allow easier comparison of information between Ncs of Parties, although no common indicators are employed.

Overview of in-depth review reports of NCs sorted by Party
Overview of in-depth review reports of NCs sorted chronologically