Le quotient familial : une structure fiscale cohérente avec le critère de Lorenz relatif

The family Quotient: a Tax Structure Consistent with the Relative Lorenz Criterion by Patrick Moyes and Alain Trannoy When households are identical in all characteristics other than income, an average rate of taxation increasing with primary income guarantees that disposable income is more evenly distributed than pretax income. This paper studies whether it is possible to obtain a similar finding with heterogeneous populations, where households can be differentiated by both income and family size. An equivalent transformation renders the income of different-sized households comparable and the tax system's redistributive capacity is evaluated by comparing Lorenz equivalent-income curves before and after taxation. We find that, when the single person is taken as the reference, most of the income tax systems in use are consistent with the goal of reducing inequalities. However, the family quotient procedure used in France is the only mechanism that makes the reduction in inequalities independent of the type of