Metadata Standards

By definition, a standard is "something considered by an authority or by general consent as a basis of comparison; an approved model." (Reference: Dictionary.com) In the context of metadataData about data. Metadata provides a context for research findings, ideally in a machine-readable format. It enables discovery of data via an electronic interface, and correct use and attribution of findings. Related Guide, metadata standard is a model to be used for metadata storage, which is approved by a standards organization (i.e. ISO, FGDCFederal Geographic Data Committee ). Metadata standards provide for the creation of "formal metadataMetadata that conforms to a specific standard, with consistent collection criteria, terminology and structure. Related Guide" with consistent collection criteria, terminology and structure.

Metadata standards specify the kinds of information required to describe data, (content, or descriptive standards), and digital storage models (format standardsA description of the digital storage and structural requirements of metadata which assures that different software programs are able to read or query the data. Related Guide). A metadata standard may include either content or format standards, or both.

Content Standard 

Content standardsA list or hierarchy of required metadata elements to be included in the metadata description. Related Guide specify the information required to document a dataset; it is a list or hierarchy of required metadata elementsIndividual instance of a metadata label and value pair. For example, "creator: John Doe" is a metadata element. Related Guide to be included in the metadata description. Content standards include things like the name of the metadata element and a definition for that name.

The "base unit" in a standard is a metadata element. Each metadata element contains specific information which, when combined with the content from other elements, completely describe a data set. A metadata standard is a collection of metadata elements combined with a set of statements that formally express the rulesIn the context of crosswalking, rules are a process which define how to deal consistently with complex element mappings. Rules are created and applied during the mapping of elements from the source schema to the target schema, when one-to-one relationships between schema elements do not exist. Related Guide of usage for these elements. This approved model, when implemented by multiple projects, helps ensure common practices across existing projects and helps users develop a sound metadata plan for a new project.

Format Standard 

Format standards describe digital storage and structural requirements of metadata. Format standards assure that different software programs are able to read or query the data. Format standards are implemented in file formats such as XMLeXtensible Markup Language , SGMLStandard Generalized Markup Language , NetCDFNetwork Common Data Format , and indented text.

By carefully articulating how the metadata elements are named, structured and utilized, metadata standards enable interoperabilityThe ability of two or more information systems to exchange metadata with minimal loss of information. Related Guide. This is also useful for users who are developing a new project. Standards can provide very specific information about details such as the range of valuesMetadata values are the content connected to metadata labels in a metadata element. For example, if the metadata label is "date", the metadata value could be "May 13, 2007". Related Guide to be provided for each element (vocabulariesA set of terms (e.g., words) that are used in a specific community. Related Guide), and how to technically present the metadata (format).

Metadata standards provide for the creation of "formal metadata" with consistent collection criteria, naming and structure. The integration of the content and technical standards concepts allows for consistency in what information is included in a metadata set, the structure that is used to store the metadata, and where the metadata are stored within this structure.

For an interesting discussion of "formal metadata", see the Metadata Challenges presentation by Dr. Sara Graves.