When it comes to the actual process of Red Listing, there are a number of key questions to consider:
Conservation assessments can be carried out using a number of different criteria systems to rank species, but the most widely used system is provided by the IUCN Red List Categories and Criteria.
Populations of animals outside the national boundaries may have positive effects on the status of the species within a country, so that certain additional considerations have to go into the assessment of extinction risk at national or regional levels.
Which species or taxa are included in the Red List exercise will be partly defined by the project scope (i.e. focus on specific taxa or a single taxon), but it also has a direct bearing on the usefulness of the resulting data (e.g. comprehensive assessments versus selection of threatened species only).