The producer price index measures the rate at which the prices of the producer goods and services are changing over time. It is key statistic for economic and business decision making and inflation monitoring. The producer Price Index Manual: Theory and Practice provides clear, up-to-date guidance on the concepts, uses, methods, and economic theory of the PPI, including information on classifications, sources , compilation techniques, and analytical uses of the PPI. The Manual supersedes the previous international guidance on PPIs (available in the Manual on Producers'Price Indices for Industrial Goods, published by the United Nations Statistics Division in 1979).