Gross Domestic Product (GDP) measures the size of an economy by the total production of goods and services in the economy. Consumer Price Index (CPI), also known as inflation, measures changes in the price level of a market basket of consumer goods and services purchased by households. Wage Price Index (WPI) measures changes in wage and salary costs for a selection of jobs, unaffected by changes in the quality and quantity of work performed. The unemployment rate indicates the number of unemployed people expressed as a percentage of the labour force in the same group.