Demand analysis requires aggregation of commodities. Some are imposed at the data collection level, leaving some for the estimation level. When data are collected, the implicit assumption underlying the aggregation is perfect substitutability: one gallon of gasoline is viewed by consumers as...

This article develops the theoretical basis of individual behaviour recovered from market behaviour in a predetermined quantities model. As applied economists argue, an inverse demand system may be empirically sound within the framework of classical demand theory. However, it should not lead to...