Statistics · Ch 1 — Index Number

Types of Index Numbers: Price, Quantity and Value

Index numbers are classified according to what they measure:

Type	What it measures	Example
Price Index Number	Relative change in the price of a commodity or group of commodities between two periods	Wholesale Price Index (WPI), Consumer Price Index (CPI)
Quantity Index Number	Relative change in the quantity produced, consumed or sold	Index of Industrial Production (IIP)
Value Index Number	Relative change in the total value (price × quantity) of a commodity or group	Index of value of exports

For a single commodity, a price relative is:

P = \dfrac{p_1}{p_0} \times 100

a quantity relative is:

Q = \dfrac{q_1}{q_0} \times 100

and a value relative is:

$V = \dfrac{p_1 q_1}{p_0 q_0} \times 100$ …