Distributive Implications of Member Level Income Aggregation within the Household : An Approximation Through Mobility Indices

This paper adapts the ethical index of income mobility first suggested by Chakravarty, Dutta and Weymark (1985) to assess the contribution of wives, husbands, and other adults' member level income to husband-wife households' income mobility according to two of the criteria discussed in the literature. For any partition of the population, a source's contribution is seen to be decomposable into within-group and between-group income mobility indices plus a term capturing sub-group differences in income shares. The approach is applied to a sample of husband-wife households where both spouses are present, extracted from the 1990-91 Encuesta de Presupuestos Familiares, the Spanish household budget survey. While the husbands' income contribution is large and positive, the contribution of wives and other adults is practically equal to zero. When mean income differences are eliminated, all member contributions to husband-wife households' income mobility are substantially reduced