Category Scheme V10

Overview

A Category Scheme is a container for Categories. An example of a category scheme is one which categorises data - sometimes known as subject matter domain scheme or a data category scheme. The individual Categories can be associated to any set of identifiable Artefacts, known as a Categorisation.

Structure Properties

Structure Type	Standard SDMX Structural Metadata Artefact
Maintainable	Yes
Identifiable	Yes
Item Scheme	Yes
SDMX Information Model Versions	2.0, 2.1
URN - CategoryScheme namespace	urn:sdmx:org.sdmx.infomodel.categorycheme.CategoryScheme
URN - categorisation namespace	urn:sdmx:org.sdmx.infomodel.categorycheme.Categorisation

Context within the SDMX 2.1 Information Model

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

Usage

Categories are used within a Category Scheme and has the facility to have one or more child codes as well as being multi-lingual.

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.

More information on Category schemes can be found in this article.

Conventions

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

Agency	Category Scheme ID ID	Description	SDMX-ML
ESTAT	ESA2010TP	ESA 2010 - Transmission programme	[ https://registry.sdmx.org/ws/public/sdmxapi/rest/categoryscheme/ESTAT/ESA2010TP/1.0 SDMX-ML]
SDMX	STAT_SUBJECT_MATTER	SDMX Statistical Subject-Matter Domains	[ https://registry.sdmx.org/ws/public/sdmxapi/rest/categoryscheme/SDMX/STAT_SUBJECT_MATTER/1.0 SDMX-ML]

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...

Concept Schemes with Simple Hierarchies

SDMX allows simple hierarchies to be defined within flat Concept Schemes by making a code the parent of codes that logically sit under it in the hierarchy.

Imagine a Concept Scheme including a Concept 'CONTACT' containing individual codes for details such as Name, Address, and Email etc. A simple hierarchy for CONTACT can be created by setting CONTACT as the parent for each of the Contact detail codes:

Code ID	Code Name	Parent
CONTACT	Contact	(none)
CONTACT_NAME	Contact name	CONTACT