There is evidence from several sources that one cannot treat many-pers
on households as a single decision maker. If this is the case, then fa
ctors such as the relative incomes of the household members may affect
the final allocation decisions made by the household. We develop a me
thod of identifying how ''incomes affect outcomes'' given conventional
family expenditure data. The basic assumption we make is that househo
ld decision processes lead to efficient outcomes. We apply our method
to a sample of Canadian couples with no children. We find that the fin
al allocations of expenditures on each partner depend significantly on
their relative incomes and ages and on the level of lifetime wealth.