Index of Industrial Production

Unlike the CPI and WPI, the Index of Industrial Production (IIP) measures quantities, not prices. Its base year is 2011-12 = 100 (with effect from April 2017); the base is refreshed often because each year some items cease to be made while new ones appear.

Where price indices are weighted averages of price relatives, the IIP is a weighted arithmetic mean of quantity relatives, the weights being each good's value added by manufacture in the base year (Laspeyre's approach):

where $q_{i1}$ is the quantity relative of good $i$ for the current year (base year 0) and $W_i$ its weight, over $n$ goods. The IIP is available by industrial sector:

and by use-based group: