Abstract: Systems and methods for measuring physician expertise are disclosed. Furthermore, systems and methods for ranking physicians based on said measure of expertise are disclosed. The systems and methods may comprise (a) capturing and mining large-scale, up-to-date medical and clinical knowledge sources (e.g., biomedical corpora, clinical guidelines, clinical trials, professional physician data); (b) building models of medical conditions that link each condition to relevant concepts (e.g., specialties, medical procedures, drug regimens) and relevant clinical research (e.g., published articles, clinical trials); (c) transforming biomedical concepts (e.g., conditions, procedures, drugs) extracted from text in natural language into terms and codes of biomedical ontologies; (d) enriching mission-critical biomedical ontologies and creating mappings between them; (e) matching physician data against a medical condition model in order to rank physicians according to their relevance to a given condition.