> It doesn't account for people buying less expensive substitutes when items get expensive as mentioned in the chained CPI FAQ, "The C-CPI-U employs a formula

> It doesn't account for people buying less expensive substitutes when items get expensive as mentioned in the chained CPI FAQ, "The C-CPI-U employs a formula that reflects the effect of substitution that consumers make across item categories in response to changes in relative prices." https://www.bls.gov/cpi/additional-resources/chained-cpi-questions-and-answers.htm https://www.bls.gov/cpi/additional-resources/chained-cpi-que...