Abstract: A method of calculating the quality of a data record having a plurality of data fields involves indentifying individual fields in the data record that are incorrect and scoring those fields accordingly. Further fields are identified where any one or more of those fields may be incorrect, but it is not immediately possible to determine which one or ones. These further fields are also scored accordingly. A score for the data records as a whole is then calculated based on the scores assigned to individual fields. Different fields may be weighted according to their importance to the data record as a whole.