Item Scheme V11

An Item Scheme is any SDMX Artefact that contains items. An item is an ‘identifiable’ but not ‘maintainable’.

Item Schemes provide the building blocks for data collection and dissemination. Item Schemes include:

• Category Schemes: Category Schemes provide the means to categorise any other structure type. Typically, Categories are used to categorise Dataflows to assist in data discovery in a dissemination environment.

• Concept Schemes: Concept Schemes are a container for Concepts. Concepts are used by Dimension, Attributes, Measures, and Metadata Attributes to provide semantic meaning.

• Codelists: Codelists provide an enumerated list of allowable content. Codelists can be used by Dimensions, Concepts, and Metadata Attributes to define the allowable content for both data and metadata reporting.

• Codes in a Codelist are all maintained in a single flat list. Each Code may define a parent Code Id, however the parent Code must exist in the same Codelist. This enables standard Codelists to define a simple Hierarchy. A simple Hierarchy may be used for data display, or for data collection (see Reporting Constraints).

• Value List: A Valuelist is a managed list of values, similar to an SDMX Codelist but unlike a Code the Value Id does not need to conform to the SDMX ID Type as it is not an official part of the SDMX Specification. Valuelists provide an enumerated list of allowable values, for which there is also a mandatory Name and optional description. This list can be referenced for defining the set of allowed values for enumerated Components in Data Structure Definitions (DSDs) or Metadata Structure Definitions which describe Reference Metadata.