Controlled vocabulary is an organized arrangement of words and phrases used to index content and/or to retrieve content through browsing or searching. It typically includes preferred and variant terms and has a defined scope or describes a specific domain.

Controlled vocabularies such as those in a taxonomy, thesaurus, and ontology, are the main terminological resources that play a key role in developing the information architecture for online portals and search platforms.

Taxonomies provide the hierarchical categorization and classification of content into subject categories and also help to categorize and classify products and brands represented in online directories and product catalogs.

Thesaurus and lexicons provide the expanded terms of the basic taxonomic classification to incorporate user variants and improve the recall efficiency of the search and retrieval process.

Ontology provides the semantic description for the taxonomy terms and establishes the relationship between categories to facilitate conceptual search and natural language queries.

In a controlled vocabulary, we strive for disambiguation, the restriction and clarification of meaning. We want to determine and define what exactly is meant by each term.

In a multidisciplinary thesaurus, one very common cause of ambiguity is identical terminology in different domains. In a very, very general sense, it means the same thing in more than one discipline – a system with two things in it. But that certainly isn’t specific to any or all of those disciplines, nor is it a useful concept for indexing content or organizing knowledge.

Vocabulary standards are important, this we know. This is true regardless of the subject matter – be it medical coding or liquor. A large part of what we work on in taxonomy development is vocabulary control. Our classification of knowledge involves designing controlled vocabularies and getting them into a form that we can use many, many times. We also have to do some linguistic analysis of the data to make sure that our terms are working correctly.

How the content or vocabulary is classified impacts findability. Professionals should look for a group experienced in solid standards-based taxonomies to associate content for appropriate machine-assisted indexing.

Melody K. Smith

Sponsored by Access Innovations, the world leader in thesaurus, ontology, and taxonomy creation and metadata application.