This assessment was undertaken to determine whether or not CLOCKSS meets the commitments it has made regarding the long-term preservation of e-journal content for the research community, and whether the repository’s operations comply with established criteria for trusted digital repositories.  The assessment included a review of information independently gathered by CRL from published and unpublished sources, a review of documents and documentation provided by CLOCKSS, and a site visit to test and verify certain repository processes and functions.  Updated documentation was provided in 2018.  The documentation was reviewed to ensure that CLOCKSS continues to comply with established criteria for trusted digital repositories.

CRL conducted its audit with reference to:

• generally accepted best practices in the management of digital systems
• the interests of the CRL community of research libraries
• the practices and needs of scholarly researchers in the humanities, sciences, and social sciences in the United States and Canada
• the criteria enumerated in Trustworthy Repositories Audit & Certification: Criteria and Checklist^[1]
• the criteria included in Audit and Certification of Trustworthy Digital Repositories (TDR) checklist (ISO 16363)^[2]
• the Open Archive Information System reference model (OAIS)^[3]
• other metrics developed by CRL in its analyses of digital repositories.

The primary metrics used by CRL in its assessments are those specified in the Trustworthy Repositories Audit and Certification (TRAC) checklist. TRAC was developed by a joint task force formed by the Research Libraries Group (RLG) and the National Archives and Records Administration in 2003 to provide criteria for use in identifying digital repositories capable of reliably storing, migrating, and providing long-term access to digital collections. TRAC represents best current practice and thinking about the organizational and technical infrastructure required for a digital repository to be considered trustworthy and thus worthy of investment by the research and research library communities. The approved ISO standard for Trustworthy Digital Repositories (ISO 16363), was also used in this audit. CRL certification is based on TRAC criteria.

It should be noted that CRL certification of CLOCKSS applies specifically to the repository’s ability to preserve and manage in digital form e-journals contributed by publishers. CRL did not assess other types of content preserved by CLOCKSS.