The Producer Price Index is based on prices paid for supplies and inputs by:

1. The two main indices track different buyers. 2. The Consumer Price Index is the most commonly cited measure. 3. The Producer Price Index is a different measure. 4. It is based on prices paid for supplies and inputs by producers of goods and services. _Source: OpenStax Principles of Macroeconomics for AP Courses 2e (CC BY 4.0), Ch 8 'Inflation'_