Type or Individual? Evidence of Large-Scale Conceptual Disarray in Wikidata

The distinction between types and individuals is key to most conceptual modeling techniques. Despite that, there are a number of situations in which modelers navigate this distinction inadequately, leading to problematic models. We show evidence of a large number of modeling mistakes associated with the failure to employ this distinction in the Wikidata knowledge graph, which can be identified with the incorrect use of instantiation, which is a relation between an individual and a type, and specialization (or subtyping), which is a relation between two types.