A method (10) for analyzing blood pressure measurements to determine any contextual or measurement tester related cause of the outlier. The method comprises identifying an obtained measurement as an outlier by comparing it with historical measurements for the subject. Any possible contextual cause of the outlier is first determined based on data in a database of contextual data for the subject. A database of historical measurement data for the tester who collected the measurement is then accessed and a determination made as to whether the outlier is attributable to the tester. Finally, the measurement, outlier status and any identified contextual or outlier-attributable cause are output. In embodiments, the measurement may be appended to a database, labelled as a true measurement and/or labelled with a cause for outlier status. Appending as a true measurement may be performed dependent on no determination being made of a contextual or tester-related cause of the outlier.
