The common yardstick that measures the objective being maximized. In project financial analysis this yardstick is the real income change for the project participants valued in domestic market prices. In project economic analysis, because the scope of the analysis differs, and because domestic market prices do not always reflect the scarcity value of project outputs and inputs, this yardstick is the real change in net national income for the project as a whole valued in economic prices. Generally, the real change in net national income can be measured at two different price levels. These are the domestic price level, where all economic prices are expressed in their equivalent domestic market price level values (the domestic price numeraire), and the world price level, where all economic prices are expressed at their equivalent world market price level values (the world price numeraire). As long as consistency is maintained in a particular calculation across all project effects, project decisions will not be affected by whether the domestic price level or the world price level is used to express the numeraire.

a traded asset that can be used as relative measure of value