As others have pointed out, this is handled differently in the UK versus the US. You are correct for the US standard definition of CPI, but the author of the a

As others have pointed out, this is handled differently in the UK versus the US. You are correct for the US standard definition of CPI, but the author of the article is a professor in the UK, writing on a UK domain for a (primarily) UK audience. Here's a link that another poster provided that summarizes the UK definitions: https://www.thetimes.co.uk/money-mentor/article/rpi-versus-cpi/ https://www.thetimes.co.uk/money-mentor/article/rpi-versus-c....