Concept Scheme V10

Overview

A concept scheme is a container for Concepts. A concept associates an identifier with a name and optional description. Their purpose is to provide other structures a semantic meaning.

Concepts may be referenced by multiple structures in SDMX, and therefore provide re-useable mechanism for giving meaning to structures.

A Data Structure Definition (DSD) provides a good example of how Concepts are used as to create a DSD. When defining a Data Structure Definition, each Dimension, Attribute and Measure is given a specific Concept. The dimensions etc do not have names or descriptions, instead they provide a reference to a Concept which gives this information. In order to get a human readable name for a Dimension, the referenced Concept must first be obtained.

Structure Properties

Structure Type	Standard SDMX Structural Metadata Artefact
Maintainable	Yes
Identifiable	Yes
Item Scheme	Yes
SDMX Information Model Versions	1.0, 2.0, 2.1
URN - ConceptScheme namespace	urn:sdmx:org.sdmx.infomodel.conceptscheme.ConceptScheme
URN - concept namespace	urn:sdmx:org.sdmx.infomodel.concept.Concept

Context within the SDMX 2.1 Information Model

The schematic illustrates the core artefacts of the SDMX 2.1 Information Model, and how Concepts Schemes and Concepts fit in.

Concepts are referenced directly by Data Structure Definitions (DSD). Concepts can also be linked to Codelists to explicitly define the set of legal values for enumerated Dimensions or Attributes.

Usage

Concepts are used by Dimensions, Attributes, Measures, and Metadata Attributes to provide them with a semantic meaning. Concepts can also be used to define a default representation, for example it is possible to link the Concept of Frequency to a Codelist containing all the Frequency Codes, any structure using the Concept will inherit the default representation.

The SDMX Cross Domain Concept Scheme provides a range of standardised Concepts maintained by the SDMX Statistical Working Group (SWG) and can be viewed on the Global Registry site https://registry.sdmx.org/items/conceptscheme.html.

An extract is shown below.

Note that the concept Civil Status has been coded and references the Codelist CIVIL_STATUS, viewing that Codelist displays valid codes.

Using standardised Concepts wherever possible is good practice because it enables harmonisation of statistics i.e. it’s easy to compare statistics produced by different organisations if referenced concepts mean the same thing.

Conventions

Concept Scheme IDs IDs are conventionally uppercase using underscores '_' as separators if required. Examples:

Agency	Concept Scheme ID	Description	SDMX-ML
ESTAT	CS_NA	List of concepts for National Accounts DSDs	SDMX-ML
UIS	CS_BOP	Balance of Payments Concept Scheme	SDMX-ML
IMF	CS_EDUC_UOE	EDUC_UOE Concept Scheme	SDMX-ML
SDMX	CROSS_DOMAIN_CONCEPTS	SDMX Cross Domain Concept Scheme	SDMX-ML

You can seem more examples and information on Identities in this article.

Flat Concept Schemes

Flat Concept Schemes are simple lists of codes with no explicit or implied relationships or hierarchies.

Example: SDMX Cross Domain Concept Scheme

Code ID	Code Name	Description
ACC_CONV	Accounting conventions	Practical procedures, standards and other aspects used when compiling data from diverse so...
ACCURACY	Accuracy	Closeness of computations or estimates to the unknown exact or true values that the statistics w...
ACTION_TYPE	Action type	Behaviour to be undertaken by a system processing the information contained in a SDMX mess...
AGE	Age	Length of time that an entity has lived or existed.
CIVIL_STATUS	Civil status	Legal, conjugal status of each individual in relation to the marriage laws or customs of the countr...