Exploring ontology metrics in the biomedical domain

Ontologies are gaining popularity in many domains as a way of representing, dealing and reasoning with large volumes of information, and they are starting to play a major role in computational science applications, e.g. in biomedical studies. The creation and maintenance of ontologies has become an engineering process that needs to be managed and measured. Therefore, as part of any ontology engineering processes, metrics can play a role helping in identifying possible problems or incorrect use of ontology elements. However, empirical studies that measure existing ontologies and set standard values are required for metrics to be effectively used. This paper reports a preliminary exploration of ontology metrics from a large set of ontologies extracted from the Open Biomedical Ontologies (OBO) repository. In this paper, we also present an ontology metrics tool, called Ontometrics, used to collect the set of metrics presented. Results show that such metrics can help identifying peculiarities of the ontologies that could be used as the basis for future ontology metric evaluation studies. © 2009 Published by Elsevier B.V.