The Red List Index (RLI) shows trends in the extinction risk of sets of species. It requires data from repeated assessments of species using the Red List categories and criteria, which are far more commonly available than detailed reliable time-series of population abundance data. Because such data are generally available for entire suites of species (e.g. all regularly occurring species in a country for a particular taxonomic group) they produce less-biased indicators than those based on a sample selected better-studied species.

• Metadata Factsheet
• BIP: Red List Index