| Weights are used to specify how large a proportion of the total index a sub-grouping of goods or services should comprise. In the Consumer Price Index, sub-groups such as transport and food are weighted on the basis of the proportion these groups comprise of an average household's consumption. For example, around 11 per cent of consumer spending is on food, and food prices thus constitute 11 per cent of the total Consumer Price Index. Weights can be expressed as fractions which sum to 1, percentages which sum to 100, or as thousandths. |