Sensitivity Analysis in Two-stage DEA with Interval Data

In Data Envelopment Analysis(DEA) an be evaluated performance of processes which can be divided into two stage, so that the first stage uses inputs to generate output which became the inputs to the second stage. The first stage outputs are referred to as intermediate measures. The second stage then uses these intermediate measures to produce outputs, and the overall efficiency is expressed as a (weighted) sum of the efficiencies of the individual stages. When some outputs and inputs are interval data, then decision making units (DMUs) can divide to three classes as follows: (I) efficient in any cases, (II) efficient in maximal sense and inefficient in minimal sense, (III) always inefficient. In this paper, we discuss an approach for assessing the sensitivity of efficiency and inefficiency classifications in two-stage DEA with interval data in above three cases. Also we find radius of stability for all DMUs.