Departmental seminar at Department of Computer Science, university of Birmingham, 6 November, 2014 abstract: Ontologies are complex knowledge representation artefacts used across biomedical sciences, the media and other domains for defining terminologies and providing metadata. Their use is increasing rapidly, but so far, ontology authoring tools have not benefited from empirical research into the ontology authoring process. Understanding how people build ontologies is key to developing tools that can properly support common authoring activities. In this talk I will first present the outcomes of qualative interviews with ontology authors and the issues it reveals. Second, I will present the results of a study that identifies common activity patterns through analysis of the event logs, screen capture and eye-tracking data collected from the popular authoring tool, Protege. Results from this bottom-up investigation suggest that the class hierarchy is the central focus of activity, playing a role beyond simple class representation. We also find that checking how updates to the ontology is hard and performance is hindered by inadequate support in the user interface. From this investigation we propose design guidelines for bulk editing, efficient reasoning and increased situational awareness in ontology authoring.