A weighting system assigning a coefficient to each member of the household and used to compare standards of living between households of different sizes and compositions. With this weighting, the number of people is converted into a number of consumption units (CU). To compare the standard of living of households, consumption per person is not satisfactory, as the needs of the household do not increase proportionally to its size.
When several people live together, it is not necessary to multiply all the consumer goods (in particular durable consumer goods) by the number of people in order to keep the same standard of living. Therefore, to compare the standards of living of households of different sizes or compositions, we use a measurement of income corrected by the consumption unit using an equivalence scale.
The most widely used scale at present (known as the OECD scale) uses the following weighting :
- 1 CU for the first adult in the household ;
- 0.5 CU for the other persons aged 14 years or older ;
- 0.3 CU for the children under 14 years.