MAST Professional is an instance of MAST Online which is only available to MAST member organisations who have access to elements of STATS19 data which is considered by the Department for Transport to be particularly sensitive or confidential in nature. In particular, this includes dimensions produced by analysing contributory factor data.
MAST Professional only includes information related to crashes which were attended by a police officer who assigned at least one contributory factor to the crash. Historical data is only available from 2006 onwards. Therefore, the Crash Officer Attended dimension is not present, since all included crashes were attended by definition.