Abstract: Knowledge deficiency of an expert system (110) is alleviated by automating extraction of data that is relevant to the expert system's diagnostics knowledge database (112) and automatically and in an on-going manner updating the knowledge database with the extracted information. Evolving diagnostic knowledge in a domain is represented in the form of semi-structured natural-language reports (116). A computer-implemented tool (120) analyzes (206) a report to determine its kind, and then employs (222) an intelligent filter (124,126) corresponding to that kind of report to parse (224-244) the report's sections, to extract (226-244) data therefrom, and to perform consistency checks (228, 234) between sections on the extracted data. The computer then assembles (248) the extracted data into database records and includes (250) them in the knowledge database.