es of effectiveness.  When 
evaluated together, metrics can be used to judge the overall suitability of a repository 
to be trusted to provide a preservation environment that is consistent with the goals of 
the OAIS. Separately, individual metrics or measures can be used to identify possible 
weaknesses or pending declines in repository functionality. 
AUDIT AND CERTIFICATION OF TRUSTWORTHY DIGITAL REPOSITORIES 
CCSDS 652.0-M-1 
Page 1-3 
September 2011 
– Sections 3 to 5 provide the normative metrics agai