How to register a controlled vocabulary

The function of the Registry of Controlled Vocabularies is two-fold:

  • To provide a metadata repository of controlled vocabularies used in resource discovery metadata by GC departments and agencies.
  • To make the vocabularies available to search engines, information creators and those involved in developing and maintaining vocabularies.

A vocabulary can be registered by submitting the required information using the rules and criteria listed below.

Registration of a vocabulary does not constitute official sanction of the vocabulary by Library and Archives Canada or the Treasury Board Secretariat, Canada.

Before developing a new controlled vocabulary, federal organizations should consult the Guide for the Development and Maintenance of Controlled Vocabularies in the Government of Canada and the Government of Canada Metadata Implementation Guidelines for Web Resource Discovery.

The Government of Canada wishes to limit the number of recognized schemes used by its organizations. In so doing, it ensures that schemes meet the basic requirements of a controlled vocabulary and limits interoperability issues that may be caused by a multiplicity of schemes.


A. Criteria for registering controlled vocabularies

  1. Controlled vocabularies, including thesauri, flat lists of preferred terms and value sets or additional standardized lists may be registered if deemed to be of use within the Government of Canada context.

    "Controlled vocabulary" is a general term for a list of standardized terms used for indexing and information retrieval usually in a defined information domain. It is characterized by consistent format, syntax and may include synonyms and cross-references. In a controlled vocabulary, one of a set of possible terms representing a concept is chosen as the representative term for that concept (preferred term). Consequently, all resources about that particular concept, within a body of information resources, can be indexed using the representative term.

    A thesaurus is a tool used for vocabulary control. Using a thesaurus improves search results. A thesaurus is a sub-set of the language we use in daily life. It includes information about the relationships of words and phrases (i.e. broader terms, narrower terms, preferred terms, non-preferred, or related terms). A thesaurus is normally restricted to a specific subject field (e.g. health, education, government documents). It allows searchers to use terminology they are familiar with to find the most relevant information.

    A flat list of preferred terms is an established list of standardized terminology for use in indexing and retrieval of information. It may or may not be arranged in alphabetical order and it does not display relationships between terms. A flat list is normally restricted to a specific kind of information (e.g. types of documents, categories of users). It is usually relatively short.
  2. Vocabularies developed and maintained within the GC are registered.

    GC-owned vocabularies must be created and maintained by trusted authorities.

    A trusted authority has a mandate within the department to develop and maintain the vocabulary. Examples of trusted authorities within the GC include centers of expertise such as the Statistics Canada Library and Information Centre, the Depository Services Program at Public Works and Government Services Canada, and the Intellectual Management Office of Library and Archives Canada, as well as entities creating and maintaining specialized vocabularies, such as Health Canada.
  3. GC-owned vocabularies must be bilingual.
  4. GC-owned vocabularies must be publicly available on the Web.
  5. Well known externally-maintained controlled vocabularies are also part of the registry. These vocabularies are added by LAC if they are determined to be of use to GC organizations. To request the addition of a non-GC-owned vocabulary, contact

B. Vocabulary titles

  1. Controlled vocabularies will be named with their official titles. The name of the organization maintaining or owning the list is rarely sufficient since it does not unambiguously stand for the vocabulary alone.
  2. Titles of controlled vocabularies are provided in all languages for vocabularies that are bilingual or multilingual.

    Statistics Canada Thesaurus and Thésaurus de Statistique Canada

  3. Vocabularies that are derived from, modified and/or translated by someone other than the original owner should be assigned a local name based on the service, project or provider name.

    The Canadian Heritage Information Network (CHIN) has developed a French version of a subset of the Art and Architecture Thesaurus (AAT), an English language tool, to describe resources in its collections. This vocabulary, though based on the AAT, would be registered with a local name.

C. Vocabulary labels

Labels are needed for machine identification of the vocabularies. They are used as scheme names in metadata elements requiring the use of controlled vocabulary.

Vocabulary labels will be assigned by the departmental registering agent using the following guidelines:

  1. Labels must be unique.
  2. Existing official acronyms or short names may be used as labels.
  3. Official government FIP (Federal Identity Program) acronyms may be used in labels.
  4. The first two letters of the label for all schemes developed specifically for use in the GC must be gc. No punctuation is included.

    Statistics Canada Thesaurus = gcstc

    Government of Canada Core Subject Thesaurus = gccore

    Note: labels do not need to be bilingual as the label is for machine rather than human use.

D. Who may register a controlled vocabulary

  1. The trusted authority/maintenance agency or an authority acting on their behalf, will submit a registration form to the controlled vocabulary registrar at LAC.
  2. LAC will register well known externally owned vocabularies on behalf of the GC. Questions should be addressed to

E. How to register a vocabulary

For all vocabularies, GC-owned or externally maintained, please contact