Another difference in the weights is that the PCE price index uses time-varying weights, while the official CPI keeps weights fixed for a year. The PCE price index weights change to reflect changes in the goods consumers buy.
Kazi Abdul Muktadir: Tackling financial exclusion in Pakistan through branchless banking Chief guest address by Mr Kazi Abdul Muktadir, Deputy Governor of the State Bank of Pakistan, at the Branchless Banking Commercial Launch of Waseela Microfinance Bank Limited, Karachi, 12 November 2012.