The Bank of Canada Commodity Price Index (BCPI) summarizes the price movements of 23 commodities produced in Canada. Information provided by the BCPI is used in analyzing movements in GDP, industrial producer prices, inflation, and the exchange rate. Effective 15 May 2003, a number of changes will be reflected in the BCPI. To ensure that the index accurately reflects the natural resource sectors of the economy, a number of new components and pricing sources have been incorporated into the BCPI. Weights in the new index will be chained to 1 January 1991 and 1 January 2000 to better reflect contemporary values.