Issues on DEA network models of Fare & Grosskopf and Kao

Classic models in data envelopment analysis view DMUs as black boxes. These models consider only the DMU's inputs and outputs in evaluation and discard individual process performance and relationship between them. For this reason, they seem to be of less applicability in evaluation of network systems. In this regard network systems were introduced. Fare and Grosskopf in 2000 and Kao in 2009 represented two network models. Since then, many researchers used these models for efficient analysis of real world systems and industries. This paper discuses specification and weakness of these two models from a comparative point of view. Finally a network system is presented in which these two models are equivalent.