When to use InformationRequirement in addition to Criterion?

[jimjyang]

In the example criterion Entitlement to marry in 10. Examples, the example Criterion ex:criterion (an instance of cv:Criterion) refers to ex:informationRequirement (an instance of cv:InformationRequirement) which in turn refers to ex:informationConcept (an instance of cv:InformationConcept) and ex:constraint (an instance of cv:Constraint) in order to express the criterion that the applicant must be at least 18 years old. However, if I understand the CCCEV-model correctly, ex:criterion may also refer to ex:informationConcept (an instance of cv:InformationConcept) and ex:constraint (an instance of cv:Constraint) directly, instead of via ex:informationRequirement.

Questions:

1. Any recommendation when to use the class cv:InformationRequirement in addition to using the class cv:Criterion?
2. Or asked another way: is it correct that the only (or, recommended) way to express the requested data (e.g., "the age of the applicant") needed to evaluate a criterion, is by using cv:InformationRequirement? (therefore the combination illustrated in the example in Chap. 10)