Table 3.

Five examples of ontology errors uncovered using Abstraction-Network-based QA methodologies

Ontology	Error Type	Characteristic	Error Description
NCIt	Redundant restriction	Class in small partial-area	Class Phagocytosis had two restrictions with the object property has associated location and the ranges of Cell and Phagocytic cell. The restriction with Cell was redundant, as Cell is more general than Phagocytic cell. [9]
SNOMED CT	Incorrect superclass	Class in small partial-area	The superclass Specimen from lung obtained by biopsy was incorrect. The correct superclass was Specimen obtained by fine needle aspiration procedure. [62]
GO	Incorrect superclass	Overlapping class	The DNA damage response, detection of DNA superclass of stimulus involved in DNA replication checkpoint was incorrect. [21]
SNOMED CT	Incorrect restriction	Overlapping class	The associated morphology restriction on the class Peptic ulcer with hemorrhage AND obstruction should have a range of Bleeding ulcer instead of Hemorrhage. [64]
SNOMED CT	Missing superclass	Overlapping class	The class Serum specimen from blood product was missing the superclass Blood specimen from blood product. [23]