Intertemporal separability is an almost universal assumption in empirical work on household behavior, but a good deal of recent work on consumption and labor supply suggest that it may not be tenable. The traditional weakening of this assumption is to allow for habit formation. The authors...

There is evidence that one cannot treat many-person households as a single decisionmaker. If so, then factors such as the relative incomes of the household members may affect the final allocation decisions made by the household. The authors develop a method of identifying how incomes affect...

We show that (Marshallian) income elasticities are proportional to (Frisch) own price elasticities if all goods are additively separable. This implies that luxuries are likely to be easier to postpone. It also implies that preferences over "consumption" are unlikely to display a constant...