http://hl7.org/fhir/StructureDefinition/itemWeight|5.2.0

A numeric value that allows the comparison (less than, greater than) or other numerical manipulation of a concept (e.g. Adding up components of a score). Scores are usually a whole number, but occasionally decimals are encountered in scores. Note: This extension used to be called http://hl7.org/fhir/StructureDefinition/ordinalValue