45. The object types are more extensively described in the next section, which contains the main list of object types and their attributes.
Classification Family: A Classification Family is a group of Classification Series related from a particular point of view. The Classification Family is related by being based on a common concept (e.g. economic activity).
Classification Series: A Classification Series is an ensemble of one or several consecutive Statistical Classifications under a particular heading (for example ISIC or ISCO).
Statistical Classification: A Statistical Classification is a set of categories which may be assigned to one or more variables registered in statistical surveys or administrative files, and used in the production and dissemination of statistics.
Level: A Statistical Classification has a structure which is composed of one or several Levels. A Level often is associated with a concept, which defines it. In a hierarchical classification the Classification Items of each Level but the highest are aggregated to the nearest higher Level. A linear Statistical Classification has only one Level.
Correspondence Table: A Correspondence Table expresses the relationship between two Statistical Classifications.
Classification Index: A Classification Index is an ordered list (alphabetical, in code order etc) of Classification Index Entries. A Classification Index relates to one particular or to several Statistical Classifications.
Classification Item: A Classification Item represents a Category at a certain Level within a Statistical Classification. It defines the content and the borders of the category. An object/unit can be classified to one and only one Classification Item at each Level of a Statistical Classification.
Map: An expression of the relation between a Classification Item in a source Statistical Classification and a corresponding Classification Item in the target Statistical Classification.
Classification Index Entry: A Classification Index Entry is a word or a short text (e.g. the name of a locality, an economic activity or an occupational title) describing a type of object/unit or object property to which a Classification Item applies, together with the code of the corresponding Classification Item.