This letter explores the robustness (in an approximating sense) of a class of demand systems which have been discussed by Gorman. This class is of fundamental interest because it is known to be the only class of demand systems which permits exact aggregation. We discuss the reasons which...

In this paper we explore the following fundamental question: Are there reasonable conditions under which the parameters of estimated aggregate demand systems will uniquely identify underlying individual demand systems? In the process of examining this question we show that the conditions which...