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[edit] Introduction to Best Practices for Shareable Metadata
[edit] What you will find in the Best Practices for Shareable Metadata
The Shareable Metadata Best Practices is divided into four main sections:
- this Introduction which provides useful background explaining the idea of 'shareable' metadata
- Best Practices for Shareable Metadata Content which includes general recommendation on authoring 'shareable' metadata, documenting decisions made about the metadata, and recommendations on how to author certain classes of metadata elements
- Best Practices for Technical Aspects of Metadata which includes recommendations for technical metadata issues including use of namespaces, XML schemas, and character encoding, and
- Final Preparations, or how to check for 'shareability' before implementing your OAI data provider
Throughout we have tried to offer specific, concrete best practices and guidelines whenever possible. However, certain sections do present either a range of choices or a spectrum of best practices from ideal to acceptable. These often represent an acknowledgement of the diversity and range of capabilities within the OAI community, and, in some cases, areas where a best practice has not clearly evolved.
Readers will notice that we do not focus on the use of unqualified Dublin Core within this document, but instead present best practices for a range of metadata formats. This is intentional, as we wish to encourage data providers to offer records not only in unqualified Dublin Core (as required by the OAI protocol), but also in other metadata formats as appropriate.
We do assume a certain practical knowledge of metadata, although we do try to provide basic definitions and examples. For more general information about metadata as well as some specific case studies, please see:
Caplan, Priscilla. Metadata Fundamentals for All Librarians. Chicago: ALA Editions, 2003.
A good introduction to a range of metadata issues and formats. Aimed at librarians but quite accessible to other communities as well.
Getty Research Institute. Introduction to Metadata: Pathways to Digital Information. (Edited by Murtha Baca) http://www.getty.edu/research/conducting_research/standards/intrometadata/index.html
Another good basic introduction to metadata.
Hillmann, Diane I. and Elaine Westbrooks, eds. Metadata in Practice. Chicago: ALA Editions, 2004.
Presents a series of case studies from libraries, museums, and other communities working with metadata. Contains some specific case studies focused on OAI and metadata interoperability.
National Science Digital Library. NSDL Metadata Primer. http://nsdl.org/collection/metadata-guide.php.
The NSDL primer for institutions interested in contributing metadata to the NSDL via the OAI protocol, but also more broadly applicable. We draw heavily on this work.
Research Libraries Group. Descriptive Metadata Guidelines for RLG Cultural Materials. 2004. http://www.rlg.org/en/pdfs/RLG_desc_metadata.pdf
Guidelines for institutions interested in contributing to RLG's Cultural Materials database, but very useful for any institution with cultural heritage materials. We draw heavily on this work.
[edit] Why best practices for shareable metadata are necessary
Participants in the Open Archives Initiative are many and diverse. Each data provider has its own needs and methods for describing its resources; therefore, metadata from one data provider may look very different from metadata from any other data provider even when in the same metadata format. This diversity, however, makes it difficult for OAI service providers to aggregate metadata from multiple data providers together in a meaningful way. The more consistent the metadata harvested by a service provider is, the more robust services that a provider can build upon it.
The best practices included here represent the consensus of participants from a range of communities. As such, they are, for the most part, not specific to a particular metadata format or to a particular community, but instead offer general guidelines and best practices. We fully expect and encourage the further adaptation of these best practices for use by specific communities and domains.
[edit] Quality metadata and shareable metadata
In a chapter entitled �The Continuum of Metadata Quality,� in the book Metadata in Practice, ed. Diane I. Hillmann and Elaine L. Westbrooks, Chicago: American Library Association, 2004, Thomas R. Bruce and Diane I. Hillmann discuss seven characteristics of quality metadata:
- Completeness. Two aspects of this characteristic are described: choosing an element set allowing the resources in question to be described as completely as is economically feasible, and applying that element set as completely as possible.
- Accuracy. This characteristic is defined as the metadata being correct and factual, and conforming to syntax of the element set in use.
- Provenance. Here provenance refers to the provision of information about the expertise of the person(s) creating the original metadata, and its transformation history.
- Conformance to expectations. Metadata elements, use of controlled vocabularies, and robustness should match the expectations of a particular community. This aspect of metadata quality is particularly problematic for OAI data providers, as sharing metadata via OAI allows it to be used by a wider variety of communities than previously targeted.
- Logical consistency and coherence. This characteristic is defined as element usage matching standard definitions, and consistent application of these elements.
- Timeliness. Two concepts make up this characteristic of metadata quality. Currency refers to metadata keeping up with changes to the resource it describes. Lag refers to a resource's availability preceding the availability of its metadata.
- Accessibility. Proper association of metadata with the resource it describes and readability by target users contribute to this characteristic.
Quality metadata may or may not be �shareable metadata�. That is, metadata may of high quality within its local context, but may be compromised when it is taken out of this context for various reasons. Shareable metadata should, of course, have these characteristics of quality metadata. However, there are some additional characteristics that make quality metadata more useful in a shared environment.
- Proper context. In a shared environment, metadata records will become separated from any high-level context applying to all records in a group, and from other records presented together in a local environment. It is therefore essential that each record contain the context necessary for understanding the resource the record describes, without relying on outside information.
- Content coherence. Metadata records for a shared environment need to contain enough information such that the record makes sense standing on its own, yet exclude information that only makes sense in a local environment. This can be described as sharing a 'view' of the native metadata.
- Use of standard vocabularies. The use of standard vocabularies enables the better integration of metadata records from one source with records from other sources.
- Consistency. Even high-quality metadata will vary somewhat among metadata creators. All decisions made about application of elements, syntax of metadata values, and usage of controlled vocabularies, should be consistent within an identifiable set of metadata records so those using this metadata can apply any necessary transformation steps without having to process inconsistencies within such a set.
- Technical conformance. Metadata should conform to the specified XML schemas and should be properly encoded.
[edit] Benefits of creating shareable metadata
Creating shareable metadata requires an investment of time. However, there are many benefits gained from making this investment.
The first and perhaps most significant benefit to creating shareable metadata is that it will be interoperable, or meaningful when combined with metadata from other sources. By using metadata schemas and rules for creating metadata values similar to those used by others, your resources can meaningfully appear in search results alongside related resources from other metadata providers.
When creating true shareable metadata, your resources are more likely to be found when pooled together with resources from other providers, rather than not being retrieved by searchers due to inconsistencies or gaps in description. Your resources therefore will receive more exposure, and end-users will have the opportunity to make previously unseen connections between your resources and those from other metadata providers.
Finally, creating shareable metadata increases the number of access points for your resources available to end-users. Aspects of a resource not previously explicitly described are often added when metadata creators think in terms of shareable metadata.
[edit] Striking a balance between OAI data providers and service providers
Exposing metadata via the Open Archives Initiative opens content up to uses data providers might not have imagined. Data providers cannot possibly tailor their metadata specifically for all the uses a service provider might have. Therefore, service providers will generally expect to do at least a minimal amount of processing of harvested metadata to achieve their goals. However, data providers most often know more about the resources being described than any given service provider. The data provider therefore can facilitate the service provider's work by following the guidelines for shareable metadata and by creating clear documentation describing the meaning and structure of the metadata they expose.
