A tree organization principle

If you are trying to organize a subject into a set of topics and subtopics  - to form a VAR tree, consider what the narratives are that you will be forming with the nodes of the tree, and follow the principle that: if two nodes are connected by a narrative, they should be siblings rather than parent-child related. For example:

PATIENT
    CASE
        MOUTH
        HISTORY
        PRODUCT
SCHEDULE
BILLING

Here we make 'PATIENT' and 'SCHEDULE' siblings because it is natural to talk about where the patient is in the schedule. At the same time, all the dental details are localized to the children of 'CASE'.