This paper deals with an analysis of the efficiency of delivery post offices from an estimated cost frontier. Our focus is to apply a robust non parametric approach for the cost frontier estimation, called the order-m frontier, based on the concept of "expected minimum cost" and to extend it to...

In this paper, we examine the application of SFA method with time-invariant inefficiency and assess its estimation of inefficiency when applied to cross section and panel data. By using simulation methods, we look at the effect of unobserved heterogeneity on the estimates of inefficiency in both...