Leveraging Horizontal Density Differences between Ontologies to Identify Missing Child Concepts: A Proof of Concept.

Previously, we investigated pairs of ontologies with local similarities where corresponding "is-a" paths are of different lengths. This indicated the possibility of importing concepts from one ontology into the other. We referred to such structures as diamonds of concepts. In this paper, we address the question whether pairs of identical concepts in pairs of ontologies have the same children in both. Separate reviews of SNOMED CT and NCIt relative to eight other ontologies uncovered differences in child sets. We provide quantitative data concerning these differences. In cases where there are many identical children in two ontologies, the questions arise why one has more children and whether these children are "missing" in the other ontology. We performed randomized controlled trials in which a human expert evaluated the "fit for import" of such potentially missing child concepts. In two out of four studies, statistical significance was achieved in support of algorithmic import.