The consumption literature uses adult equivalence scales to measure individual-level inequality. This practice imposes the assumption that there is no within-household inequality. In this paper, we show that ignoring consumption inequality within households produces misleading estimates of inequality along two dimensions. To illustrate this point, we use a collective model of household behaviour to estimate consumption inequality in the U.K. from 1968 to 2001. First, the use of adult equivalence scales underestimates the initial level of cross-sectional consumption inequality by 50%, as large differences in the earnings of husbands and wives translate into large differences in consumption allocations within households. Second, we estimate the rise in between-household inequality has been accompanied by an offsetting reduction in within-household inequality. Our findings also indicate that increases in marital sorting on wages and hours worked can simultaneously explain two-thirds of the decline in within-household inequality and between a quarter and one-half of the rise in between-household inequality for one and two adult households.
Review of Economic Studies
D12: Consumer Economics: Empirical Analysis
D13: Household Production and Intrahousehold Allocation
D31: Personal Income, Wealth, and Their Distributions
J22: Time Allocation and Labor Supply