Population indicator: A decrease in the index means that the general trend in the size of the populations within it has decreased since the baseline year of 1970.
Harvest indicator: This index tracks sustainability using ratio between the real harvest and the ‘optimal’ level of harvest for all of the populations within it. Therefore, an increase in the index means that the harvests are less sustainable than those taken during the previous year. If the index decreases, the ratio between these two variables is lower so more of the harvests are sustainable.
Price indicator: An increase in the index means that the price of the wild commodities has increased more during the previous year than the price of the baseline commodities (e.g. non-food commodities). Conversely, if the index decreases, then the price of the baseline commodities have increased proportionally more than the wild commodities.