In the previous blog post I discussed the release of the AAT as linked open data. I’d like to further explain controlled vocabularies, the AAT, and the concept of linked open data—for my own understanding! I’ve found the Getty guides to be good sources of clearly-written, thorough information, so I consulted the Getty Introduction to Controlled Vocabularies by Patrica Harpring as well as our textbook, Metadata for Digital Collections.
According to Harpring, controlled vocabularies:
- are information tools containing standardized words and phrases in an organized arrangement
- allow for the categorization, indexing, and retrieval of information
- enable browsing and searching in a digital repository
- are employed with goal of information discovery, collocation, and comparison
- typically include preferred and variant terms
- have a defined scope
- are standards for data values
We have been learning about standard metadata elements, the categories of description, in such schemas as Dublin Core and MODS. Controlled vocabularies include the values entered in those element categories.
Controlled vocabularies help solve the problem of human language when searching for information in a digital environment. For example, the same word can refer to different concepts or things—or, the same concept, thing, person can have different names and spellings. The computer can’t infer meaning from context the way we do in natural language, so terms have to be made explicit for the computer to find the exact information you are seeking. Controlled vocabularies come to the rescue by standardizing terminology.
Controlled vocabularies can also arrange terms in hierarchical relationships by indicating terms are more broad or narrow, and in associative relationships by indicating related terms.
In our textbook, Miller points out that “communities create controlled vocabularies to serve certain functions in an information organization and retrieval environment.” The AAT is such a vocabulary created for a community of users.
The most common types of controlled vocabularies for art and architecture are:
- subject headings list
- simple and controlled lists
- synonym rings
The Art and Architecture Thesaurus is a controlled vocabulary for describing art, architecture, and cultural items. More to come on AAT in next blog post.
Introduction to Controlled Vocabularies, by Patricia Harpring
Metadata for Digital Collections, by Steven J. Miller