For estimating distributions from grouped data, setting up moment conditions in terms of group shares and group means leads to an optimal weight matrix and a GMM objective function that are considerably simpler than those from a previous specification. Minimization is more efficient and...

A derivative-based measure of economies of scope is obtained by exploiting the duality between the shadow cost function and the input distance function. This is a useful measure when the econometric estimation of a cost function is not viable.