External non-discretionary variables in Data Envelopment Analysis

We encounter with a real case including non-discretionary inputs and outputs with different classifications involving internal and external factors in addition to discretionary variables. Purpose of this paper is a developed model based on DEA for a corrected efficiency assessments taking into account the effect of external non-discretionary factors. The reason is that most of the current DEA literature on non-discretionary variables assume just non-discretionary input (output) and present an input (output) oriented model accommodating non-discretionary variables. They consider neither both ND inputs and outputs simultaneously nor classification of them into internal and external ND factors. In order to provide reliable estimate of efficiency, it is significant to use an appropriate programming model