Digital repositories are often thought of primarily as a computer system, consisting of hardware, software and networks, but they are more than this. Digital repositories are organisations similar in purpose to libraries or archives and, just as it does for these organisations, quality assurance should form an integral part of the work of a digital repository.
A digital repository should:
A digital repository intent on long-term retention of its holdings should conform to the Reference Model for an Open Archival Information System (OAIS) [1].
Useful information is available in the QA Focus Briefing papers on "From Project To Production Service" [2] and "Planning An End User Service" [3].
Quality assurance can be incorporated into the work of a digital repository through the establishment of formal (but not necessarily complex) policies and procedures.
The CEDARS project suggested that collections management policies should cover: selection, acquisition, organisation, storage, access (user registration and authentication, delivery of masters versions), de-selection, and preservation. Policies developed to cover these topics should be subject to internal and external review as part of a formal approval process. Policies should be reviewed at regular intervals.
Policies should be written to conform to the requirements of relevant legislation, notably the Data Protection Act, 1998.
The day-to-day operation of the repository should be connected to its overall policy framework through the development of procedures. Procedures should be:
Digital repositories need to make use of a wide range of standards and best practices for data creation, metadata creation, data storage, transmission and for many other areas. Many of these topics are discussed in more detail in other QA Focus documents. Selection of technical standards should take particular account of the guidance in QA Focus briefing papers on "Matrix for Selection of Standards" [4] and "Top Tips For Selecting Open Source Software" [5].
A digital repository should operate within a clear legal framework that establishes the rights and responsibilities of the repository, its depositors and its users. A formal agreement should be established between each depositor and the repository, by way of a signed licence form or other technique (unavoidable online licence agreement).
This agreement should limit the liability of the repository (e.g. where a depositor does not have copyright), while conferring the repository with rights to manage or withdraw content. Otherwise, the depositor's rights should be protected and any limits on the service provided by the repository should be made clear (such as limits on how long data will be stored, and whether migration or other preservation actions will be undertaken).