>Output is measured primarily as an index of product revenues, adjusted for price changes https://www.bls.gov/k12/productivity-101/content/how-is-productivity-

>Output is measured primarily as an index of product revenues, adjusted for price changes https://www.bls.gov/k12/productivity-101/content/how-is-productivity-measured/output.htm#:~:text=For%20industries%2C%20BLS%20uses%20annual,annual%20and%20quarterly%20productivity%20measures https://www.bls.gov/k12/productivity-101/content/how-is-prod... Adjusted for price changes being the key word. The BLS isn't measuring the number of pipes plumbed. They're counting the dollars that plumbers make and using that number to determine their output. To compare that output across time you have to discount for inflation. If you calculate too high a rate of inflation then you discount too much