Macroeconomics studies the overall economy and aggregates like total output, income, employment and prices. It examines how the whole economy behaves, including why economic activity rises and falls. Macroeconomists analyze indicators like GDP, unemployment, inflation, interest rates, stock markets and exchange rates. GDP measures the total value of final goods and services produced domestically in a year. Other key concepts include consumption, investment, and the relationship between gross domestic product, gross national product, net domestic product and national income.