Interoperability across two or more heterogeneous clinical medical error taxonomies can be improved by associating categories in various taxonomies with one or more categories in a master taxonomy. These associations can be expressed using a unique identifier, e.g., a number that identifies one or more categories in the master taxonomy. Various aspects of the associations and/or one or more master taxonomies can be modified by users of a system employing embodiments of the technologies described herein. Searches of clinical medical error records can also be aided using the technologies described herein.