4.10 How an individual price change impacts the total index

When the price of alcohol, petrol or cars goes up or down, Statistics Finland is often asked to what extent these changes impact the whole consumer price index, i.e. the rate of inflation. A change in the price of a Karelian pasty (which has a weight of 0.05 per cent in the total index) has a lesser impact on the index than a change in the price of cars (which is weighted at 5.19 per cent)

The impact of the change in prices on the total index depends on

the weight of the commodity relative to the weight of the total index (0.05/100 - 5.19/100)

the price development for the commodity from base period to the point of measurement relative to the development of the total index (for example, from 2000 to September 2003).

In order to calculate the price impact of an individual commodity or group of commodities, we need to know

the index value of the commodity concerned at the point of measurement and at the point of comparison

the weight of the commodity concerned

the overall value of the consumer price index at the time of comparison

Examples

4.1

4.2

4.3

4.4

4.5

4.6

4.7