Scale flexibilities in inverse demand systems describe how marginal valuations change with expansions in the consumption bundle. Such effects clearly are related to income elasticities in direct demand systems. However, the connection is not so close as it first appears. We argue that the link...

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...