Metadata Enables Access to a Unified Collection
This guidance describes the approach to metadata for digital content that is selected for the Library's permanent collections.
Digital content in the Library’s collection exists as part of a unified collection that is both analog and digital. In this regard, it is a general best practice for descriptive metadata for any digital content to be produced and managed in the same systems in which analog collection materials metadata are managed. For example, eBooks are described with Machine Readable Cataloging (MARC) records alongside print books. Born digital manuscript collection content is described alongside analog collection content in finding aids. The production and management of inventory metadata for analog and digital content may necessitate the use of different systems; while the Library currently manages the inventory of analog content in the same systems that house descriptive metadata, inventory information related to digital content is typically recorded elsewhere.
In keeping with the understanding that there is a unified Library collection, metadata directives and policies apply equally to all materials. In general, Directives about cataloging and metadata policies produced and maintained by the Policy and Standards Division, Network Development and MARC Standards Office, Integrated Library System Program Office, as well as individual curatorial units with expertise about specific format types and storage requirements also apply to digital content. This guidance describes baseline metadata requirements necessary for the Library's management of digital content.
All content in the permanent digital collection should be managed through the use of a metadata schema, as is appropriate to the complexity, extent, and custodial history of the content in question. As a leader and participant in the digital library community, the Library of Congress promulgates and stewards international standards. We use these standards to direct and inform the management of digital content in the Library's collections. Although the majority of the Library's collections are published materials and described by records in the MARC format, this standard is not necessarily suitable for the complex array of the Library's vast holdings. Due to the Library's diversity of collections and formats; range of organizational units including the Law Library and Library Services; and variety of platforms and management tools, no single standard governs metadata for the Library's digital content. For example:
- MARC records, searchable in the Library's online catalog, describe books, ebooks, and other items;
- METS, ALTO, and MARC records describe and manage digitized newspaper content in the Chronicling America collection;
- EAD provides structured, searchable context for manuscript collections and associated digital content;
- MODS records describe the Web Archives.
During planning for content acquisition and processing, if no metadata schema is identified or found to be suitable, then a project should aim to follow guidelines such as the Library's common list of data elements for digital content as published in the Library of Congress Metadata for Digital Content (MDC). Projects that use MDC should choose a subset of these elements and indicate the MDC fields used in a metadata profile, including any attributes or encoding conventions adopted. Profiles will include details about attributes used, encoding conventions, and authority lists or other controlled vocabularies used. Project-specific elements should be identified in specific profiles. In general, the MDC can help to provide a simplified implementation of MODS and METS standards.