The purpose of the WPI is to monitor price movements that reflect supply and demand in industry, manufacturing and construction.
However, United States now report a producer price index (PPI) instead.
The commodities chosen for the calculation are based on their importance in the region and the point of time the WPI is employed.
[1] Currently the base year has been revised from 2004-05 to 2011-12 by the Office of Economic Advisor(OEA), Department for promotion of industry and internal trade Ministry of Commerce and Industry to align it with the base year of other macro economic indicators like the gross domestic product (GDP)and Index of Industrial Production (IIP).
[2] Under primary article group of the new WPI there are 117 items against earlier 98, while fuel and power category remains static at 16.