In order to ensure global uniformity when describing the habitat in which a taxon occurs, the threats to a taxon, what conservation actions are in place or are needed, and whether or not the taxon is utilized, a set of standard terms (called Classification Schemes; formerly referred to as Authority Files) have been developed for documenting taxa on the IUCN Red List. These Classification Schemes are still being developed and tested and not all of them have been implemented in this version of the IUCN Red List.
The Classification Schemes for Threats and Conservation Actions Needed underwent a major review as part of a joint initiative between the IUCN Red List Partnership and The Conservation Measures Partnership, and are now in use (for further details about the schemes, see www.conservationmeasures.org/initiatives/threats-actions-taxonomies). For an explanation of the Threats and Conservation Actions Needed Classification Schemes, please read the Conservation Biology 2008 article: A Standard Lexicon for Biodiversity Conservation: Unified Classifications of Threats and Actions.
The Classification Schemes used in the Red List assessments include:
Note that the guidance documents attached above to each Classification Scheme are working drafts and that whilst the Classification Schemes themselves may not change, the definitions, examples and guidance on use will be periodically updated as indicated by the date shown alongside each attachment. Also note that the Stresses, Conservation Actions in Place and Research Needed schemes are not currently displayed on the Red List web site. If the timing, scope and severity of the threats is recorded, an impact score of the threats is automatically calculated based on the values in the attached table, however, this information is also not displayed on the Red List web site as it has not been captured for most species.