Create a controlled vocabulary to improve metadata findability and give stakeholders a quality experience

September 19, 2023

Controlled vocabulary is a structured and organised system of terms used to describe concepts, ideas, and objects within a specific application, system or database. It serves as a crucial tool for enhancing precision and consistency in information management, particularly in fields such as libraries, information retrieval, data indexing, and content categorisation. An excellent strategy for use in tagging, keywords, digital asset management systems (DAMS) or Product information management systems (PIMS). Establishing a controlled vocabulary ensures users can effectively communicate, retrieve, and navigate information, ultimately reducing ambiguity and facilitating accurate knowledge representation.

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In the realm of information management, the proliferation of digital content has led to a pressing need for efficient and accurate ways to categorise, index, and search for information. Controlled vocabulary addresses this challenge by providing a standardised set of terms that are predefined and carefully selected. These terms, also known as descriptors, encompass the most important concepts within a given subject area, specific to organisational and stakeholder needs.


Principles of Controlled Vocabulary

  1. Consistency: Controlled vocabulary ensures consistent representation of concepts. Unlike free-text searching, where synonyms, homonyms, and variations can lead to confusion, controlled vocabulary dictates a single term for each concept. For example, in a library catalog, the controlled term ‘automobile’ might encompass variations like ‘car’ or ‘vehicle’.

  2. Precision: Controlled vocabulary enhances search precision by minimising irrelevant results. For instance, a search for ‘apple’ might yield pages about both the fruit and the technology company. Controlled vocabulary differentiates between the two by assigning distinct terms like ‘fruit’ and ‘Apple Inc’.

  3. Hierarchy: Often, controlled vocabularies are organised hierarchically. This hierarchy establishes broader categories and more specific terms within those categories. For instance, within the category of ‘animals’, you might find terms like ‘mammals’, ‘birds’, and ‘reptiles’.

  4. Relationships: Controlled vocabulary systems can incorporate relationships between terms, such as synonyms, broader/narrower terms, and related terms. This helps users navigate between concepts and find relevant information more efficiently. For example, ‘cat’ might be related to ‘pet’, ‘feline’, and ‘kitten’.


Examples of Controlled Vocabulary in Action

  1. Library Classification Systems: The Dewey Decimal Classification (DDC) and Library of Congress Classification (LCC) are examples of controlled vocabularies used in libraries. Books are categorised using assigned numbers or codes, allowing users to locate specific subjects easily. For instance, under DDC, books about astronomy might be classified under ‘520’.

  2. Medical Subject Headings (MeSH): In the field of medicine, MeSH is a controlled vocabulary maintained by the National Library of Medicine. It covers various medical concepts and allows precise indexing of articles in databases like PubMed. For instance, ‘diabetes mellitus’ is a specific MeSH term under which related research is categorised.

  3. Thesauri: Thesauri like Roget’s Thesaurus provide controlled vocabulary for synonyms and related terms. Instead of using various words for ‘happy’, the thesaurus suggests alternatives like ‘joyful’, ‘content’, and ‘elated’.

  4. Art and Cultural Heritage: In art museums and archives, controlled vocabulary aids in categorising and searching for artworks, artefacts, and historical documents. For example, the Getty Art & Architecture Thesaurus includes terms like ‘impressionism’ and renaissance’.

  5. Online Retail: E-commerce platforms use controlled vocabulary to categorise products for efficient navigation. If a customer searches for ‘sneakers’, the system might also show results under terms like ‘trainers’, ‘athletic shoes’ or ‘running shoes’.


Benefits and Challenges

Controlled vocabulary offers numerous benefits, including improved search accuracy, efficient data organisation, and standardised communication. However, challenges include keeping the vocabulary up to date with evolving terminology, accommodating cultural differences, and ensuring that the vocabulary remains relevant in rapidly changing fields.

Findability and stakeholder experience

If data and assets are considered important and sustainable for an organisation then controlled vocabulary is a foundational tool. By providing standardised terms, hierarchies, and relationships, it enhances the accuracy and efficiency of information retrieval, enabling users to effectively navigate the vast digital landscape while minimising confusion and ambiguity. From libraries and medical research to e-commerce and cultural heritage, controlled vocabulary continues to play a vital role in shaping the way we access, comprehend and share information in an increasingly interconnected world.

Controlled Vocabulary