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Controlled Vocabulary

A Controlled Vocabulary is a defined set of equivalent words (synonyms) used in the context of a product. This can include terms for interactions (for example, “search” and “lookup”) or subject-specific terminology in reference to your site’s content (for example, “LP” and “album”). These will be the words used for indexing, navigation, calls-to-action, and page titles and should not be deviated from in any way that is visible to users. A Controlled Vocabulary can also contain “preferred” terms for clarity and to educate the user.

Controlled Vocabularies allow for the creation of a thesaurus for tagging and metadata, making it possible for users to find the “right” content: when searching for “fishing pole,” the system could find items associated with the preferred term, “fishing rod” and display that information to the user.

Authority Files are often part of a Controlled Vocabulary. Items in an Authority File are exclusive terms that equivalent terms are mapped to. For example, state words are always mapped to the two-digit postal code: “Delhi” is always mapped to “DL”.


Schedule Time

Time Needed: 4 – 6 Weeks

Gather Materials

Spreadsheet software



Review existing company products; document labels and terminology in a spreadsheet. Then, do the same for competitive products. In most cases, conforming to industry terminology is preferred so users can comfortably predict content and functionality.


Review your site’s search logs. Record the terms users have searched for when attempting to access a specific type of content, and map those terms to the relevant vocabulary currently in use within your existing product.


Interview users and customer service personnel to document terms used by users. If this is an internal product, interview users in every department and, if possible and applicable, every location.


Map these terms to the other spreadsheet terms.

  • Decide if your Controlled Vocabulary will contain nouns, verbs and adjectives. For example, the names of products (“Raid Flying Insect Spray’), what the products do (“kill wasps”) and how the products are described by users (“stinging bug spray”). Map these terms to the other spreadsheet terms, where applicable.

  • Decide which terms will have spelling variations and misspellings (“Coke”, “Cola”, “Coola”). Map these terms to the other spreadsheet terms.

  • Decide which terms need singular and plural variants (“robot”, “robots”). Some search engines have this setting.

  • Decide which terms require abbreviations and acronyms (“Tex”, “Lone Star State”, “Tejas”). Map these terms to the other spreadsheet terms.

  • Decide which terms have multiple meanings and may need multiple entries. You will need to ask the user to choose which term they are searching for.

  • Ask stakeholders and users to review the spreadsheet.


Try these tips

  • Ask if the product needs search before undertaking the creation of a Controlled Vocabulary. (Not every product needs one, especially if there is no commitment to maintain it.)

  • Ask who will maintain the Controlled Vocabulary.

  • Don’t minimize the effort to create a Controlled Vocabulary.

  • Taxonomies may be available for your domain or industry from third parties.

Explore more resources

Hedden Information Management: Taxonomies, Thesauri, and Controlled Vocabularies

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