The Mental Health Services Data Set (MHSDS) is a patient level, output based, secondary uses data set which aims to deliver robust, comprehensive, nationally consistent and comparable person-based information for children, young people and adults who are in contact with services for mental health and wellbeing, learning disability, autism or other neurodevelopmental conditions. As a secondary uses data set it re-uses clinical and operational data for purposes other than direct patient care. It defines the data items, definitions and associated value sets to be extracted or derived from local information systems.