A classification system used by the OFT for all official statistics and surveys. The full version of this classification has 17 categories. The version intended for most users, called the analytic version, has the following 8 categories: Higher managerial and professional occupations, which can be sub-divided into large employers and higher managerial occupations, and higher professional occupations; Lower managerial and professional occupations; Intermediate occupations; Small employers and own account workers; Lower supervisory and technical occupations; Semi-routine occupations; Routine occupations; Never worked and long-term unemployed.