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  1. FHIR Specification Feedback
  2. FHIR-27060

Formal Equivalence w/ CQL and UCUM durations

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    • Type: Change Request
    • Status: Applied (View Workflow)
    • Priority: Medium
    • Resolution: Persuasive
    • Specification:
      Clinical Quality Language (FHIR)
    • Raised in Version:
      1.5
    • Work Group:
      Clinical Decision Support
    • Related Page(s):
      Authors Guide
    • Related Section(s):
      4.2.1. Quantities
    • Grouping:
    • Resolution Description:
      Hide

      Agreed, add discussion of quantity equality, equivalence, and comparison with respect to calendar and definite quantity duration units to the Appendix B reference documentation.

      In addition, in the Quantity discussion, and the unit conversion discussions, make clear that definite quantity unit conversion follows UCUM conversion, and calendar duration conversion is performed as:

      • 1000 milliseconds = 1 second
      • 60 seconds = 1 minute
      • 60 minutes = 1 hour
      • 24 hours = 1 day
      • 12 months = 1 year

      Note specifically that unit conversion between (years and months) and (days or below) is not defined.

      Show
      Agreed, add discussion of quantity equality, equivalence, and comparison with respect to calendar and definite quantity duration units to the Appendix B reference documentation. In addition, in the Quantity discussion, and the unit conversion discussions, make clear that definite quantity unit conversion follows UCUM conversion, and calendar duration conversion is performed as: 1000 milliseconds = 1 second 60 seconds = 1 minute 60 minutes = 1 hour 24 hours = 1 day 12 months = 1 year Note specifically that unit conversion between (years and months) and (days or below) is not defined.
    • Resolution Vote:
      Chris Moesel/Jen Seeman: 17-0-5
    • Change Category:
      Clarification
    • Change Impact:
      Non-substantive

      Description

      The table shows relationships between CQL durations and UCUM durations using the ~ operator.  This introduces special meaning to ~ that I don't believe is specified elsewhere. If the intention is that the ~ operator should support these notions of equivalence, then that should probably be specified in discussions and definitions of ~ as well (for example, in Appendix B).

       

      The spec also may want to provide guidance for implementers regarding how to calculate equivalence in these cases.  For example, how would I evaluate the expression: 365 days ~ 1 'a'?

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              Assignee:
              bryn.rhodes Bryn Rhodes
              Reporter:
              cmoesel Chris Moesel
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