John C. Williams is President and CEO of the Federal Reserve Bank of San Francisco.

Assesses changes in the cost of living by measuring changes in the prices of consumer items. The CPI is the headline inflation figure that indicates the strength of domestic inflationary pressures.

Measures changes in the selling prices producers charge for goods and services, and well as tracks how prices feed through the production process. Because producers tend to pass on higher costs to consumers as higher retail prices, the PPI is valuable as an early indicator of inflation. Simply put, inflation reflects a decline in the purchasing power of the Dollar, where each dollar buys fewer goods and services. The report also gives insight into how higher prices from raw materials flow toward the final product.

A rise in PPI signals an increase in inflationary pressures. Given the economic instability associated with rising price levels, the Fed often will raise interest rates to check inflation. A low or falling PPI is indicative of declining prices, and may suggest an economic slowdown.

The headline figure is expressed in percentage change of producer price.

Notes: The PPI records prices at various stages of production: raw goods, intermediate goods and finished goods. Though intermediate and crude goods prices do provide insight for future inflationary pressure, it is the price of finished goods that generates most interest for market participants. The finished goods data is able to gauge price pressure before the goods reach the retail market.