Preservation metadata

Strengths and weaknesses of the PREMIS Data Dictionary

Understandable, on the whole.
Allows references to external sources of information, e.g. format registries and policies.
XML schemas available.
Supported and maintained by an international editorial committee based at the Library of Congress.
Several digital repositories are investigating PREMIS.
Requires establishment of preservation policy to enable preservation level to be specified.
Grew out of the practical experience of numerous institutions; it is therefore based on consensus and oriented towards implementation.
Flexibility: no requirements as to how preservation information is stored.
Generality: applicable to all types of digital material, from personal digital archives to eBooks.
It can be incorporated into a METS file and therefore combined with other metadata to create an Information Package.
Ability to link between entities, establishing one-to-one, one-to-many and many-to-one relationships.
Applicable regardless of object type.
Repeatable semantic units allow more or less granularity, as required.
Very few of the PREMIS semantic units are mandatory.

Many find the Representation concept difficult to grasp.
Requires agreement on business rules.
Requires local agreement on data content standards. This means work on selecting and, in many cases, developing controlled vocabularies based on repository policies which may not yet exist in many repositories.
Need for local controlled vocabularies may reduce ease of interoperability, unless standards for these emerge.
Insufficient implementation examples (though more are emerging).
Difficult to automate creation of metadata structured as in PREMIS at present (though PREMIS does not require this).
Need to consider fit with overall metadata profile and policy framework.
Must be supplemented by metadata which can record detailed technical attributes of specific object-types, or media and hardware.
The values to populate some semantic units defined by PREMIS are currently difficult or impossible to obtain, though this is not a weakness of PREMIS itself.