The objective of this study was to determine whether structural change in the demand for butter, margarine, and salad and cooking oils occurred between 1967 and 1986. A nonparametric method, which does not require that a functional form be imposed on the data, was used to test for violations from stable, well-behaved preferences. Violations were found, but they were small in magnitude. Therefore, the results failed to show strong evidence that consumption patterns for butter, margarine, and oils were inconsistent with stable preferences.
