[DDI-ADG] nCube elements

[Mary Vardigan]

Sanda and I had a brief chat about tweaking some of the nCube elements to 
name them more appropriately or possibly eliminate them. Here is a summary 
of our discussion, along with the element descriptions from the Tag 
Library. More food for thought...

Mary


<cohort> 4.4.12.1  Cohort

    * Optional
    * Repeatable
    * Attributes: 
<http://webapp.icpsr.umich.edu/cocoon/DDI-LIBRARY/?element-definition=codeBook>ID, 
xml:lang, source, catRef, value

Description: The element cohort is used when the nCube contains a limited 
number of categories from a particular variable, as opposed to the full 
range of categories. The attribute "catRef" is an IDREF to the actual 
category being used. The attribute "value" indicates the actual value 
attached to the category that is being used.

Example(s):

<dmns><cohort catRef="CV24_1" value="1"></cohort></dmns>

We thought this might be better termed CategorySubset rather than Cohort.

____________________________


<measure> 4.4.13  Measure

    * Optional
    * Repeatable
    * Attributes: 
<http://webapp.icpsr.umich.edu/cocoon/DDI-LIBRARY/?element-definition=codeBook>ID, 
xml:lang, source, varRef, aggrMeth, measUnit, scale, origin, additivity

Description: The element measure indicates the measurement features of the 
cell content: type of aggregation used, measurement unit, and measurement 
scale. An origin point is recorded for anchored scales, to be used in 
determining relative movement along the scale. Additivity indicates whether 
an aggregate is a stock (like the population at a given point in time) or a 
flow (like the number of births or deaths over a certain period of time). 
The non-additive flag is to be used for measures that for logical reasons 
cannot be aggregated to a higher level - for instance, data that only make 
sense at a certain level of aggregation, like a classification. Two nCubes 
may be identical except for their measure - for example, a count of persons 
by age and percent of persons by age. Measure is an empty element that 
includes the following attributes: "varRef" is an IDREF; "aggrMeth" 
indicates the type of aggregation method used, for example 'sum', 
'average', 'count'; "measUnit" records the measurement unit, for example 
'km', 'miles', etc.; "scale" records unit of scale, for example 'x1', 
'x1000'; "origin" records the point of origin for anchored 
scales;"additivity" records type of additivity such as 'stock', 'flow', 
'non-additive'.

We are assuming that this element will be replaced by a "container" of 
attributes or characteristics that will apply at all levels, some of which 
J will be supplying from SDMX. Thus, the existing attributes like 
"Aggregation Method" will become part of this larger set of 
characteristics. "Measure" is a particularly problematic term because 
Nesstar uses it in a different way to mean the variable itself.

_______________________________________


<purpose> 4.4.11

    * Optional
    * Not Repeatable
    * Attributes: 
<http://webapp.icpsr.umich.edu/cocoon/DDI-LIBRARY/?element-definition=codeBook>ID, 
xml:lang, source, sdatrefs, methrefs, pubrefs, URI

Description: Explains the purpose for which a particular nCube was created.

Example(s):

<nCube><purpose>Meets reporting requirements for the Federal Reserve 
Board</purpose></nCube>

We are wondering if anyone is actually using this tag. We wonder the same 
thing about <defntn> in nCube Group and Variable Group:


<defntn> 4.1.4  Definition

    * Optional
    * Not Repeatable
    * Attributes: 
<http://webapp.icpsr.umich.edu/cocoon/DDI-LIBRARY/?element-definition=codeBook>ID, 
xml:lang, source

Description: Rationale for why the group was constituted in this way.

Example(s):

<varGrp><defntn>The following eight variables were only asked in 
Ghana.</defntn></varGrp>
<nCubeGrp><defntn>The following four nCubes form a single presentation 
table.</defntn></nCubeGrp>

Neither purpose nor definition is likely to be machine-actionable, and it 
seems that this information regarding purpose and rationale might be better 
placed in Abstract or in another text element.



Mary Vardigan
Assistant Director
Inter-university Consortium for Political and Social Research (ICPSR)
University of Michigan
P.O. Box 1248, Ann Arbor, MI 48106-1248
Phone: 734-615-7908
Fax: 734-647-8200
www.icpsr.umich.edu 
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