An economic measure of scale efficiency is the ratio of the minimum average cost to the average cost at the actual output level of a firm. It is easily measured by the ratio of the total cost of this output under the constant and variable returns to scale assumptions. This procedure does not...

In a production technology, the type of returns to scale (RTS) associated with an efficient decision making unit (DMU) is indicative of the direction of marginal rescaling that the DMU should undertake in order to improve its productivity. In this paper a concept of global returns to scale (GRS)...