(From GSIM Revision Task Team meeting; 21 Feb, 2018)
Is it useful to have both Category and Category Item in GSIM? Is Category necessary if it is just a subtype of Concept? Is Category Item necessary or could we just have Category Set?
How have countries implemented these objects? Are they using all three objects? Or some subset of them?
If one is to be removed, what would be the implication (how would it affect relationship with other objects, do we need to update attribute)?
| Object | Definition | Explanatory Text | Diagram |
|---|---|---|---|
| Category | A Concept whose role is to extensionally define and measure a characteristic. | Categories for the Concept of sex include: Male, Female Note: An extensional definition is a description of a Concept by enumerating all of its sub ordinate Concepts under one criterion or sub division. For example - the Noble Gases (in the periodic table) is extensionally defined by the set of elements including Helium, Neon, Argon, Krypton, Xenon, Radon. (ISO 1087-1) |  |
| Category Item | An element of a Category Set. | A type of Node particular to a Category Set type of Node Set. A Category Item contains the meaning of a Category without any associated representation. |  |
| Category Set | A list of Categories | A Category Set is a type of Node Set which groups Categories through the use of Category Items. The Categories in a Category Settypically have no assigned Designations (Codes). For example: |  |
5 Comments
user-8e470
We should ask Alistair Hamilton, Eva Holm and Catrin Karling, Francine Kalonji, Guillaume Duffes, Marina Signore or Mauro Scanu what they have implemented
Maybe there is a difference depending on which physical implementation standard is used/aligned to. Category is different in DDI vs SDMX.
Alistair Hamilton
Hi user-8e470. For a Node's meaning, ABS addresses Concept directly rather than having a specific subtype of Concept called Category. This was a business user driven decision, they did not want to consider and define Categories separately to Concepts in general.
The term Concept is also different in DDI vs SDMX. ABS uses the DDI sense, not the SDMX sense. From memory in SDMX Concept (while not fully developed) is kind of a "lite" proxy for use of a Represented Variable in a data structure definition (a GSIM/AIM Data Structure Component), where the Code List gives the Representation and the SDMX "Concept" gives the rest.
ABS sees Category vs Category Item / Category Set as doing different things in GSIM. Category (or a directly link to Concept in ABS) gives meaning to any type of Node.
The original intent in ABS for Category Item / Category Set (CI/CS) was for Node Sets that are not intrinsically Coded. This contrasts with Statistical Classification or (in the ABS case) Code List as both are coded. CI/CS could be used, for example, for the set of items in a small controlled vocabulary where any decision to assign codes to the items would be arbitrary.
Of course, if you start using the controlled vocabulary in statistical data you typically end up wanting codes anyway (eg seasonal adjustment types).
We have, however, ended up with "enumerations" as attributes for other AIM classes (eg types of Statistical Program, statuses of Statistical Programs). A generic way to model these controlled sets of "Category Items" within a particular "Category Set" would be using those artefacts in GSIM. ABS insisted (I am not 100% convinced) we actually needed a separate implementation for Controlled Vocabulary / Controlled Vocabulary Item - so we haven't ended up using Category Set / Category Item in practice. I could not see a case for supporting both CV/CVI and CS/CI in GSIM, but unless GSIM adds also CV/CVI then CS/CI may still have a role generically?
Francine Kalonji
Bonjour user-8e470,
In our current implementation, Category is a subtype of Concept. And Conceptual Domain contains [0..*] Category. Described Value Domain and Statistical Classification have a direct correspondance to a Conceptual Domain. The Classification Item takes its meaning from Category and has a Code attribute. We do not use Category Set/Category Item.
We do use Enumerations as attributes as well (looking at Alistair's comments). And because they are directly related to Objects, they are simply considered as Controlled Vocabularies.
user-c9ea8
DISCUSSING: Countries use controlled vocabularies rather than category sets/category items. Do we need to make a change?
user-8e470
Final thought - not enough information to make a change as part of this review.