The authors introduce a procedure for transforming any homogeneous technology into a nonhomothetic one. This procedure is particularly useful when applied to a nonseparable two-stage constant elasticity of substitution technology since the number of additional parameters to be estimated is small...

Pooling consumption data from different countries for demand system estimation is attractive because it increases both sample size and therange of v ariation of relative prices and income. The major objection to pooling is that d ifferent countries may have different demand system parameters....

The authors introduce a procedure for imposing curvature conditions locally in a class of flexible demand systems. Aside from the simplicity of the procedure, a major advantage is that flexibility is maintained. The authors illustrate the technique by estimating three flexible demand...