Efficiency of decision making units in network DEA using interval data

In this paper, the difference between multiplicative and envelopment models of network DEA is examined, in which network DEA multiplicative model is able to calculate efficiency and the envelopment model can calculate the projection on the frontier. Here, a model is presented that can calculate both frontier projection and efficiency in network DEA. Since in real world, many data are interval data, we present a model in this article that calculates the efficiency of the units being evaluated by such these interval data. Since data are as intervals, the resulting efficiencies are calculated as intervals. We present two models for calculating the lower and upper bounds for any DMU and prove that these models give upper and lower bounds of efficiency.