Methodology
The SSII can be calculated 1 as National SSII: This index measures how well, on average, species are documented in a given nation over a given timespane, in this case per year. The index value I for country C in a particular year is given by the arithmetic mean among expected species Sc of the proportion of expected cells in country C, Ec, with records from that year, Oc. Steward’s SSII: This index adjusts the national coverage based on nations’ stewardship of species, upweighting the documentation of species for which a nation has particularly high stewardship. This means the proportion of global cells that country C holds for a species. Calculations are performed over an equal area global grid of ca. 110-km resolution or which expert expectations
Data description
For a given species, the Species Status Information Index (SSII) captures how well existing data covers the species’ expected range. At the species level, the SSII can be computed across the entirety of the species’ expected range, ignoring national boundaries, or separately within each nation where it is expected to occur.