"It contains a total of 3216 terms, comprising 1430 Preferred terms and 1786 Non-preferred terms (entry terms or reference points). The structure is hierarchical, using a 'tree' structure that starts with broad concepts (top terms) which are then broken down into narrower concepts. The structure is fairly flat, with 571 top terms, and a maximum of 3-4 steps in each hierarchy. Subject thesaurus terms are used to describe the subject matter of resources - they describe what resources are about. This thesaurus is designed for post-coordinate retrieval - that is, each term represents a single concept, and as many terms as necessary may be used to describe a resource. This provides for flexibility and precision during resource discovery, because the searcher is able to combine terms to satisfy the particular enquiry. In indexing and retrieval, composite concepts may require the use of two or more keywords. For example, a resource dealing with 'computer network security' would have the TAGS terms 'Computer networks' and 'Security measures' assigned as Subject metadata.
TAGS is a thesaurus of subject terms for use by Australian Government agencies which: covers, at a high level, subject concepts representing the scope of Australian Government activities; provides a potential source of terminology for portal browse lists; and provides a subject vocabulary which is broader than the detailed vocabularies already adopted by some agencies, but which is able to function as an introduction to those detailed vocabularies, or to serve as a controlled vocabulary for those agencies without a specialised one."