The development of ontologies that define entities and the relationships among them has become essential for modern work in biomedicine. Ontologies are becoming so large in their coverage that no single centralized group of people can develop them effectively and ontology development becomes a community-based enterprise. In this paper we present Collaborative Protégé—a prototype tool that supports many aspects of community-based development, such as discussions integrated with ontology-editing process, chats, annotations of changes, and so on. We have evaluated Collaborative Protégé in the context of the NCI Thesaurus development. Users have found the new tool effective as an environment for carrying out discussions and recording design rationale.
