This is the ValueSet that contains all the codes in X12 278 Review Decision Reason Codes (http://hl7.org/fhir/us/davinci-pdex/ValueSet/X12278ReviewDecisionReasonCode) and X12 278 Review Decision Reason Codes (http://hl7.org/fhir/us/davinci-pdex/ValueSet/X12278ReviewDecisionReasonCode). E.g. what you have to deal with if you get resources containing codes in either of them