The 3 approaches to measure national income the expenditure approach, the income approach, and the value-added approach. N other issues related to national income gross national income vs. net national income, gdp vs. gnp, nominal gdp vs. real. N a simple way to measure our standard of living and compare it other countries. If we have an aggregate price, we need an aggregate output; otherwise we cannot do a demand and supply diagram. N we call the aggregate output as gross domestic product (gdp) the total value of goods and services produced in the economy. There are 3 ways to measure gdp: the expenditure approach, the income approach, the value added approach. N note: the government uses both the expenditure approach and income approach to measure gdp. The expenditure approach, sometimes called gross domestic expenditure (gde), adds up the expenditure needed to purchase the final output produced during a given period.