The purpose of this paper is to improve the statistical analysis of multiproduct firm behavior. The authors offer a new empirical technique that can be used to directly analyze issues such as subadditivity, expansion path subadditivity, economies of scope, and economies of diversification....

This paper estimates frontier cost functions for US Department of Veterans Affairs (VA) hospitals in FY2000 that are consistent with economic theory and explicitly account for cost differences across patients' risk, level of access to care, quality of care, and hospital-specific characteristics....