where to 
make the de-identification changes. For example, the Observation Resource has a subject element that 
mostly refers to a Patient resource. Should it be removed? Left and the Patient resource it refers to be de-identified? 
Updated to a new patient resource randomly or consistently? 
There are many other Reference elements on Observation that can easily be used to navigate back 
to the Subject;  e.g., Observation.context value of Encounter or EpisodeOfCare; or Observation.performer.   
These also n