Controlled Vocabularies for DDI 3: Enhancing Machine-Actionability

Controlled vocabularies (CVs) are organized lists of terms used for metadata and information retrieval. They may be short (flat) lists or more complex constructs, containing hierarchical relationships. Subject thesauri, such as LCSH (Library of Congress Subject Headings) or the multilingual ELSST thesaurus used by European data archives, are examples of the more complex constructs, containing broader terms, narrower terms, related terms, synonyms, and scope notes.