skeezyboy

Quote from https://www.bls.gov/cpi/questions-and-answers.htm BLS data collectors visit (in person, on the web, or using apps) or call thousands of retail stores, service establishments, rental units, and doctors' offices, all over the United States to obtain information on the prices of the thousands of items used to track and measure price changes in the CPI. We record the prices of about 80,000 items each month, representing a scientifically selected sample of the prices paid by consumers for goods and services purchased. During each call or visit, the data collector collects price data on a specific good or service that was precisely defined during an earlier visit. If the selected item is no longer available, or if there have been changes in the quality or quantity (for example, a 64-ounce container has been replaced by a 59-ounce container) of the good or service since the last time prices were collected, a new item is selected or the quality change in the current item is recorded.

edit: https://www.ons.gov.uk/economy/inflationandpriceindices/meth...

methodology states it is based on prices quoted