Modifiers allow to express that a fact is not a statement about a patient, but about another fact. They supplement the expressibility of CONCEPTs. The usage of modifiers is advices when:

  1. Statements are an extension to a repeatable statement (location, cuff size for blood pressure)
  2. Modifiers can be reused in many other parts of the ontology (degree of severity, level of expertise, measurement methods). One example is to differ between primary and secondary diagnose by 2 modifiers that are inherited to the whole diagnosis tree.
  3. Modifiers are used already, e.g. in a biomaterial setting: if modifiers are used for tracking number, kind of material, drawn_by, and so on, one would of course model pathogen as a modifier as well.