Principles for Evaluating Metadata Standards
The ALCTS/LITA Metadata Standards Committee has developed the Principles for Evaluating Metadata Standards for use by the library, archives, and museum (LAM) community. The principles were initially developed as an internal document as a distillation of the many lessons learned by metadata communities over time; however, the committee soon realized they could be useful to a broader audience.
The principles are intended to inform and support the development, maintenance, selection, and assessment of metadata standards. They may be applied to metadata structures (field lists, property definitions, etc.) and with content standards, controlled vocabularies, and standards intended for both system- and machine-created metadata.
It is the hope of this committee that these principles can help guide the refinement of current metadata standards, and the creation of new metadata structures and vocabularies. These principles are aspirational and may not be fully implementable as a pragmatic concern for all standards.
1. Metadata standards should be part of a shared data network
Metadata—its standards, systems, and services—is most efficient when connected with the broader network of information as manifested in the W3C’s Linked Data initiatives and related data sharing efforts. Metadata standards should provide mechanisms for expressing relationships to other vocabularies. For example, standards that allow for the use of URIs, in addition to or instead of relying solely upon strings of text, may connect information from different sources, support distribution to indexing and research services, and increase resource visibility on the web.
2. Metadata standards should be open and reusable
Open metadata is a foundational building block of information systems and computationally-enhanced research. Metadata standards and associated vocabularies need to be open for use and re-use, free of charge, and managed with openness and transparency. Metadata standards governance and maintenance bodies should consider explicit licenses that promote reusability of standards and vocabularies.
3. Metadata standards and creation guidelines should benefit user communities
The volume of information in a web-enabled world, along with the ability of information systems to analyze and index digital objects themselves, changes the value of traditional metadata. Metadata standards should be created with the intended audience, its related communities, and the public in mind. The depth and granularity defined by metadata standards should prioritize data elements that support clear use cases defined and contributed by their user communities and allow implementers to use only features relevant to their needs.
4 . Metadata standards should support creative applications
Up to the 21st Century, bibliographic metadata has supported a relatively narrow vein of research, involving reading, viewing, listening to, or otherwise engaging with individual resources by humans. As new research methods emerge (e.g., computational linguistics, computational bibliometrics, linguistic analysis, network analysis), and as new data modeling methods geared toward machine actionability mature, metadata standards and exchange/access methods should easily support evolving modeling and use practices. Encoding of metadata standards in machine-processable formats such as RelaxNG, XML Schema, or RDF Schema can help to promote computational use of metadata in emerging fields.
5. Metadata standards should have an active maintenance and governance community
Metadata standards are only as valuable and current as their communities of practice, which are changing with increasing rapidity. The needs of implementers should be a driving force for the development of standards over time. Governance bodies should support transparent, timely development and revision processes by publishing standards development and revision protocols. Such protocols should include mechanisms for community contributions to draft standards. Governance bodies should change and develop over time to reflect the diversity of their current and potential user communities.
6. Metadata standards should be extensible, embeddable, and interoperable
Central to the successful deployment of a metadata standard is its ability to be used effectively alongside other standards. Standards should be designed in a modular way to allow relevant parts to be incorporated into local systems together with parts of standards from other sources, with each given equal preference. Relatively complex standards should provide “lite” style implementation options, to allow for wider adoption and utility, even if this means lossy data transfer in some cases. “Lite” style implementations are helpful in enhancing interoperability of metadata standards that have differing underlying intellectual models.
7. Metadata standards should follow the rules of “graceful degradation” and “progressive enhancement”
Metadata standards should be designed such that, as the complexity of the standard is stripped away, the metadata degrades gracefully. Removing complexity, for example to make metadata that is encoded according to a robust standard useful to a less specialized audience or to remove sensitive information, should result in metadata that is still useful. Metadata standards that are designed from a progressive enhancement approach prioritize simplicity while being flexible enough to support enrichment of the standard to accommodate specialized metadata use cases.
8. Metadata standards should be documented
Alongside the metadata standard, information about its use in practice, examples of the standard as applied to a real-life resource, its governance and management structure, rationale behind design decisions, and its connections to metadata standards from other domains should be published. Efforts should be made to allow easy adaptation of documentation for multilingual environments and to make the documentation understandable to implementers from other fields. Applying a license to the documentation will clarify its use and reuse.
9. Metadata standards should be inclusive and transparent about historical and cultural biases
Metadata standards development is not neutral; human beings unavoidably assign value judgments when making (and not making) assertions about a resource, and in defining the assertions that can be made about a resource. Metadata standards developers should be aware of these value judgments, make them explicit to the degree possible, and take as a guiding principle not neutrality, but rather inclusivity of worldviews. A diversified team approach can be considered in the creation, implementation, and further enhancement of the metadata standards. Metadata standards and vocabularies should reflect changes in language.