<status value="active"/> <experimental value="false"/> <date value="2014-03-26"/> <description value="Only with service events. A person witnessing the action happening without doing anything. A witness is not necessarily aware, much less approves of anything stated in the service event. Example for a witness is students watching an operation or an advanced directive witness."/> <immutable value="true"/> <compose> <include> <system value="http://terminology.hl7.org/CodeSystem/v3-ParticipationType"/> <filter> <property value="concept"/> <op value="is-a"/> <value value="WIT"/> </filter> </include> </compose> </ValueSet>