[DDI-users] Variable representation: measurementUnit, WeightVariableReference, StandardWeightReference

[My Coyne]

Hello,

I am learning about Variable: 
-- A variable associates with 0..* QuestionReference
-- A variable associates with 0..* VariableName (really?)
-- A variable associates with 0..1 Representation
          * A representation has measurementUnit
          * A representation associates with 0..* WeightVariableReference
          * A representation associates with 0..* StandardWeightReference

My questions:
(1)  Under what circumstance a variable will have more than one names?  Furthermore, how does an entity queries the information would know 
which variable name to use?
       This leads to another question:  If in question q1, the variable name is V1; but in question qn, the variable name is Vn.  How to indicate 
such "order" with QuestionReference and VariableName.  Because it seems that in such case the QuestionReference and VariableName is 
"tightly coupled" and I don't know how the schema can enforce this.

(2) What is WeightVariableReference and StandardWeightReference?  why are they not just as simple as a string value of the measurementUnit?

Thank you for your help.

My Coyne
mcoyne at boninc.com
(cel): 301-399-6351