This paper provides an empirical application of Lee and Pitt’s (1986) approach to the problem of corner solutions in the case of panel data. This model deals with corner solutions in a manner consistent with the firm behavior theory while controlling for unobserved heterogeneity. In this...

Usually firms operate with a restricted number of energy sources. In the dairy industry, most firms have multi-energy systems allowing them to shift from one energy source to another at almost no cost. Zero expenditures are observed because firms minimize costs and non-negativity constraints on...