A hierarchical organization of terms or ideas that allows aggregation into categories.
- A statistical classification
- Allows categories to be counted and compared, without double counting.
- Is a
, which mean that each node in the is included in only one node in the level above. Although this avoids double counting, it means that arbitrary decisions are made when a node is naturally related to more than one parent.
- In a statistical classification such as , bacterial pneumonia is related to lung disorder or infectious disorder, but not to both.
Hierarchy Illustration - Statistical Monohierarchical Classification
- In contrast, a
such as SNOMED CT, enables bacterial pneumonia to be a subtype of both lung disorder and infectious disorder. This enables more inclusive analytics and avoids overlooking conditions that are in a different category from the one being analyzed.
Hierarchy Illustration - Subtype Polyhierarchy