To fix the scales of compulsory levies and social benefits for households of different size and composition, public authorities rely on the equivalence scale. Accounting for economies of scale achieved in households (shared public goods), the equivalence scale allows to calculate the additional amount of expenditures or income of a given household, in order to reach the utility level of a one-person household. The value of the equivalence scale depends on the consumption structure or equivalently the lifestyle of households. Is the equivalence scale currently used (applicable to the entire population) and implemented in the 1990s still relevant despite the changes in lifestyles ? Are they adapted to senior households (60 years and more) and working-age households (less than 60 years) whose consumption structure is different from that of the whole population ? How has consumption-specific scales evolved since the 1990s ? This paper uses survey data on family budget (les enquêtes budget
des familles) from 1979 to 2010 to estimate the overall equivalence scales applicable to (i) the general population, (ii) subpopulations of seniors and (iii) working-age households as well as (iv) the consumption- specific scales. Our results suggest that the implemented scale in the middle of 1990s is still adapted to current lifestyle. However, this scale underestimates the living standards and economies of scale achieved in senior households and overestimates those of the working-age
households.