Provides information regarding whom or what the variable/nCube describes. DDI provides a Controlled Vocabulary for this location: "AnalysisUnit" PLEASE NOTE A CHANGE IN USAGE INSTRUCTIONS: The string content of "concept" now contains the language specific label obtained from the controlled vocabulary. This allows for multiple languages through the repeated entry of the "concept" element. The attribute "vocabInstanceCodeTerm" has been added to accommodate the code term as it appears in the controlled vocabulary. See the high level documentation for a complete description of usage. The full element may be repeated only to support multiple language expressions of the content.