Therefore, by adding all of the sources of income together, a quick estimate can be made of the total productive value of economic activity over a period. What Is the Expenditure Method? Quantitatively, the resulting GDP is the same as aggregate demand because they use the same formula. There are four main aggregate expenditures that go into calculating GDP: consumption by households, investment by businesses, government spending on goods and services, and net exports, which are equal to exports minus imports of goods and services. Conversely, the income approach starts with the income earned wages, rents, interest, profits from the production of goods and services. Partner Links. Short-run aggregate demand only measures total output for a single nominal price level, or the average of current prices across the entire spectrum of goods and services produced in the economy.