Abstract
This paper employs a cone-homogeneous production function to approximate, as closely as desired, a ray-homogeneous production function. Points in input space are projected by an output scaling function on to a fixed ray and a Cobb-Douglas cone function is used to obtain an estimate of global returns to scale. The empirical results indicate that we get a good approximation to a ray-homogeneous production function from the estimated cone-homogeneous function.