Gross domestic product
Gross domestic product (GDP) is a monetary measure of the market value of all the final goods and services produced in a period of time, often annually 
GDP (nominal) per capita does not, however, reflect differences in the cost of living and the inflation rates of the countries; therefore using a basis of GDP per capita at purchasing power parity (PPP) is arguably more useful when comparing differences in living standards between nations.
Gross domestic income
In the United States, the Bureau of Economic Analysis produces figures for both the GDP and GDI. Although these should be equal, since they are calculated in different ways, in practice, the listed figures are different. This difference is known as the statistical discrepancy.