flexible and integer data in two-stage network dea

The standard dea method requires that the status of all input and output variables be known exactly. however, in many real applications, the status of some measures is not clearly known as inputs or outputs. these measures are referred to as flexible measures. conventional data envelopment analysis (dea) models assume real-valued inputs and outputs. in many occasions, some inputs and/or outputs can only take integer values. in this paper a new method is proposed to evaluate the efficiency and to determine the status of flexible measures in the presence of integer data in basic and general two-stage network structures.