08afeb41_Model___UNECE_Statistics_Wikis__Object
[Group] Concepts [Definition] A structured list of mutually exclusive Categories. Such a structured list may be linear or hierarchically structured. [Explanatory Text] Classification Scheme has two subtypes - Classification Version and Classification Variant. In a hierarchical Classification Scheme, Categories organized into Levels determined by the hierarchy. The Categories in each Level are mutually exclusive and exhaustive. [Object] 
Classification Scheme
Annex C Glossary - Generic Statistical Information Model - UNECE Statistics Wikis