"A group or question item from the original questionnaire for which answers are provided." - HL7 FHIR, QuestionnaireResponse.item Note that in FHIR, this construct appears to duplicate the Item construct in the Questionnaire resource (in FHIM called the QuestionnaireItem), apparently in order to convey a minimal amount of information for when the QuestionnaireItem is not available. Ordinarily, we would have just pointed directly to the QuestionnaireItem, but the usage is subtely different between ResponseItem and QuestionnaireItem, so for now, we've modeled this as two separate classes.