Clinical Metadata Exploration Ontology (CMEO) clinical data category subset is record of process time to event measurement record A timestamped measurement datum that documents the elapsed time from a specified reference time point (e.g., baseline, diagnosis, treatment start) to the occurrence of a specified event, typically expressed in a time unit. The reference time point and the event type should be explicitly stated or linked (e.g., time to death, time to rehospitalization, time to first myocardial infarction). time stamped measurement datum