A new standard concept property for order should be added to the standard code system  concept properties  code system; and added to the  Defined Concept Properties  section in the CodeSystem resource type page.  This property can be used to support representation of values like severity in code systems. Concept in concept properties code system code: order display: Order definition: Order of the concept amongst sibling concepts as a decimal value.  Defined concept properties page URL:  http://hl7.org/fhir/concept-properties#order  : decimal Description: A property that indicates the order of the concept amongst its siblings in the code system e.g. severity. The code system specific purpose of the ordering is defined elsewhere.