Abstract :
In a recent paper by Shetty and Pakkala [U. Shetty, T.P.M. Pakkala, (2010), Ranking efficient DMUs based on single virtual inefficient DMU in DEA. OPSEARCH, 47 (1):50-72], they proposed an approach to rank the efficient decision making units based on a virtual DMU. The input and output levels of this virtual DMU are the average of input and outputs of all DMUs. They showed that, if there exist at least one inefficient DMU then this virtual DMU is inefficient. Also, based on this virtual DMU they proposed a model for ranking efficient DMUs. This brief comment provides an alternative analytical and direct proof for their main theorem.
