Metadata, data about data, are data describing the form and content of documents, objects or services. Metadata may be part of the informative objects themselves or separated from them. Well-known metadata are the catalog records for printed publications and index databases. The term metadata gained influence with the raise of Internet-based information resources.

There are many standards for metadata. Some are general and some are domain specific. A well-known standard is the Dublin Core scheme. It contains the following element description:

• Subject: The topic addressed by the work
• Title: The name of the object
• Author: The person(s) primarily responsible for the intellectual content of the object
• Publisher: The agent or agency responsible for making the object available
• OtherAgent: The person(s), such as editors and transcribers, who have made other significant intellectual contributions to the work
• Date: The date of publication
• ObjectType: The genre of the object, such as novel, poem, or dictionary
• Form: The data representation of the object, such as Postscript file or Windows executable file
• Identifier: String or number used to uniquely identify the object
• Relation: Relationship to other objects
• Source: Objects, either print or electronic, from which this object is derived, if applicable
• Language: Language of the intellectual content
• Coverage: The spatial locations and temporal durations characteristic of the object"

Doctorow (2001) warns against underlying assumptions about metadata:

 "A world of exhaustive, reliable metadata would be a utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. His main arguments are based on seven obstacles:

1. People lie

2. People are lazy

3. People are stupid

4. Mission: Impossible -- know thyself

5. Schemas aren't neutral

6. Metrics influence results

7. There's more than one way to describe something

Perhaps we could say Doctorow's first arguments supports the idea that some institutionalized authority should take care because otherwise the job is not done properly. The last three arguments supports the domain analytic point of view that metadata should be produced for a particular domain and perspective, and that universal solutions are problematic.

Hawking & Zobel (2007) test the claim that topic metadata can be used to improve the accuracy of text searches by examining the contribution of metadata to effective searching within Web sites published by a university with a strong commitment to and substantial investment in metadata. The authors use four sets of queries, a total of 463, extracted from the university's official query logs and from the university's site map. The results are clear: The available metadata is of little value in ranking answers to those queries. A follow-up experiment with the Web sites published in a particular government jurisdiction confirms that this conclusion is not specific to the particular university. Examination of the metadata present at the university reveals that, in addition to implementation deficiencies, there are inherent problems in trying to use subject and description metadata to enhance the searchability of Web sites. The experiments show that link anchor text, which can be regarded as metadata created by others, is much more effective in identifying best answers to queries than other textual evidence. Furthermore, query-independent evidence such as link counts and uniform resource locator (URL) length, unlike subject and description metadata, can substantially improve baseline performance.

Literature.

Beall, J. (2006). Metadata and Data Quality Problems in the Digital Library. Journal of Digital Information, 6(3), article no. 355, 2005-06-12.  http://jodi.tamu.edu/Articles/v06/i03/Beall/

Doctorow, C. (2001). Metacrap: Putting the torch to seven straw-men of the meta-utopia. http://www.well.com/~doctorow/metacrap.htm

Gorman, M. (1999). Metadata or Cataloging? A False Choice. Journal of Internet Cataloging 2(1), 5-22.

Gorman, M. (2000 ). From Card Catalogues to Webpacs: Celebrating Cataloguing in the 20th Century. Presented at: Library of Congress Bicentennial Conference on Bibliographic Control for the New Millennium Washington, D.C., November 15th 2000. Available at: http://loc.gov/catdir/bibcontrol/gorman_paper.html

Hawking, D. & Zobel, J. (2007).  Does topic metadata help with Web search? Journal of the American Society for Information Science and Technology, Published Online: 2 Feb 2007

Haynes, D. (2004). Metadata for information management and retrieval.  London: Facet.

Vellucci, S. L. (1998). Metadata. Annual review of information science and technology, 33, 187-222.

See also: Indexing languages; Information retrieval languages

Birger Hjørland

Last edited: 14-02-2007

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