The CPI does have formal methods for attempting to account for this: https://www.bls.gov/cpi/quality-adjustment/questions-and-answers.htm https://www.bls.gov/c

The CPI does have formal methods for attempting to account for this: https://www.bls.gov/cpi/quality-adjustment/questions-and-answers.htm https://www.bls.gov/cpi/quality-adjustment/questions-and-ans... This can occasionally result in odd things, like when the introduction of unlimited cell phone data plans led core inflation to drop one month for first time in seven years: https://www.wsj.com/articles/BL-REB-37505 https://www.wsj.com/articles/BL-REB-37505