Since 2006, CSI companies participating in GNR have used independent third party limited assurance of their CO2 emissions information. Other participants are strongly encouraged to adopt data assurance practices as part of their participation. This assurance process is managed at a company level and involves potential visits by the independent assurance provider to a sample of a company’s facilities. The number and location of such visits is determined solely by the assurance provider, and must be stated in their assurance summary.

Of the 2008 data submitted to the GNR, 73% has been assured independently at company-level, with some company assurance programs still in progress.