Fluid Milk Purchases: A Multivariate Tobit Analysis

We formulate an econometric model of fluid milk expenditures, taking into account two important characteristics: expenditures may be censored at zero and may be interdependent across milk type. Censoring of fluid milk expenditures is addressed with a generalized Tobit system estimator. Interdependence of milk expenditures is examined through a likelihood function with no restrictions on elements of the Engel curve error covariance matrix. Expenditure function parameters are estimated using a March 1991 to March 1992 U.S. consumer panel.