Moschini, GianCarlo

American Journal of Agricultural Economics Vol. 77 no. 1 (February 1995): 63-68.

The Stone index typically used in estimating linear almost ideal demand systems is not invariant to changes in units of measurement, which may seriously affect the approximation properties of the model. A modification to the Stone index, or use of a regular price index instead, are both desirable practices in estimating linear AI models.