The availability, exchange and interpretation of taxonomic information (such as species check lists, distribution and identification data) is of critical importance to taxonomists, ecologists and other biologists and legislators, amongst others. This information is provided by a number of global and local taxonomic database services. These databases hold records, often based on valid scientific names for species, according to their own models of what constitutes a taxonomic 'entity' or concept (i.e. a species or higher level taxon). Databases typically model a single view of taxonomy, whilst making some attempt to relate their concepts to synonymous names or concepts.

The rules and history of taxonomic nomenclature mean that scientific names do not unambiguously identify taxonomic concepts as represented according to different models of taxonomy. Therefore the same name will apply to different taxon concepts according to different taxonomic viewpoints (conversely, very similar concepts according to alternative taxonomies may sometimes be given different names). The problems inherent in using names as identifiers are recognized and might be addressed by representing richer taxon concepts, based on a name plus a reference to the definition of the concept or at least by capturing the usage of that name according to some original taxonomic source.

The need for a common mechanism for the providers of taxonomic information to exchange information with other providers and users of varying expertise in taxonomy was recognized at TDWG Lisbon 2003. Such a mechanism must adequately represent the data as modelled by the owners of the data, whist facilitating integration with data provided according to different models of taxonomy.

The development of an abstract model for a taxonomic concept, which can capture the various models represented and understood by the various data providers, is central to this project. This model is presented as an XML schema document that is proposed as a standard to allow exchange of data between different data models. It aims to capture data as understood by the data owners without distortion, and facilitate the query of different data resources according to the common schema model.

Also see UsingTheSchema and WhoDefinesTaxonConcepts.