Measuring Inefficiency Slacks of Network Systems in the presence of ‎Shared Resources

Performance evaluation is one of the important tasks of management in order to better understand the ‎past successes of a manufacturing unit and plan for its future development. The goal is to determine ‎whether the unit can be expected to increase its output with current input, or while maintaining the ‎current production output, how much savings in input can be made merely by increasing efficiency. A ‎system is usually composed of multiple parts, each with a specific function. When we are interested in ‎the performance of the system as a whole unit, where only inputs coming into the system and outputs ‎going out of the system are considered, it is called whole unit or black box analysis, because how ‎inputs are converted into outputs through intermediate products is not considered. The whole unit ‎analysis provides a general idea of the performance of a unit. However, since the system usually ‎consists of several interrelated parts, ignoring the functions of constituent parts may cause misleading ‎results. To properly evaluate the performance of a system, this article proposes a set of additive ‎models. The proposed models measure the inefficiency slacks of a system from both optimistic and ‎pessimistic views. Therefore, an overall performance evaluation for each system is obtained. An ‎example of the banking industry in Iran is offered to explain how to calculate the inefficiency slacks ‎of the system and processes.‎