The SACC has a three-level hierarchical structure.
The third, and most detailed level, of the main classification structure consists of the base units which are countries as described above (see Definition of country). The classification consists of 245 third-level units including five 'not elsewhere classified' categories which contain entities that are not listed separately in the classification (see Reserved codes for residual categories).
The second level of the main classification structure comprises 27 minor groups, which are groups of neighbouring countries similar in terms of social, cultural, economic and political characteristics. Each minor group lies wholly within the boundaries of a geographic continent. On average minor groups contain 9 countries, with individual minor groups containing between 1 and 27 countries.
The first, and most general, level of the main classification structure comprises nine major groups which are formed by aggregating geographically proximate minor groups and, therefore, comprise countries which are broadly similar in terms of social, cultural, economic and political characteristics. Each major group lies wholly within the bounds of a single geographic continent (with two exceptions: North Africa and the Middle East, and Americas). On average, major groups contain three minor groups, with individual major groups containing between two and six minor groups.
The SACC also includes a set of alternative standard groupings of countries based on economic and political criteria to facilitate its use in an extended range of applications. The alternative groupings are, in the main, conventional, internationally recognised associations or organisations of member countries or economies which serve economic and political purposes. These groupings are not part of the main structure (see Use of the SACC for economic statistics, and Alternative country groupings). A number of authorised standard output options (such as the former USSR) which are not part of the main structure, are provided as output options to facilitate time series maintenance (see Authorised standard output options).