Definition of 'Chain-Weighted CPI'
An alternative measurement for the Consumer Price Index (CPI) that considers product substitutions made by consumers and other changes in their spending habits. The chain-weighted CPI is therefore considered to be a more accurate inflation gauge than the traditional fixed-weighted CPI, because rather than merely measuring periodic changes in the price of a fixed basket of goods, it accounts for the fact that consumers’ purchasing decisions change along with changes in prices. Because the fixed-weighted CPI may consistently overstate inflation by ignoring the disinflationary effect of quality improvements and new technology, in addition to the substitution effect, the U.S. Bureau of Labor Statistics maintains that the chain-weighted CPI is a closer approximation to a cost-of-living index than other CPI measures.
Chain Weighted CPI Definition | Investopedia