On the Concept of Efficiency Prabhat Patnaik While a vectorwise larger output for given endowments would constitute an improvement in the efficiency of resource use, such an improvement does not follow from the replacement of an activity set with a lower marginal rate of transformation of one set of goods into another by another activity set with a higher rate. It would follow if the economy always had full employment of resources, but it does not; hence the two perceptions of efficiency are not synonymous.