[3] Output is the result of an economic process that has used inputs to produce a product or service that is available for sale or use somewhere else.
One may also deduce the ratio of marginal costs as the slope of the production–possibility frontier, which would give the rate at which society can transform one good into another.
Output can be sub-divided into components based on whose demand has generated it – total consumption C by members of the public (including on imported goods) minus imported goods M (the difference being consumption of domestic output), spending G by the government, domestically produced goods X bought by foreigners, planned inventory accumulation Iplanned inven, unplanned inventory accumulation Iunplanned inven resulting from incorrect predictions of consumer and government demand, and fixed investment If on machinery and the like.
This identity is distinct from the goods market equilibrium condition, which is satisfied when unplanned inventory investment equals zero: Output is the result of an economic process that has used inputs to produce a product or service that is available for sale or use somewhere else.
Exchange of output between two countries is a very common occurrence, as there is always trade taking place between different nations of the world.