An extended data envelopment analysis (DEA) model

Considering the conventional data envelopment analysis (DEA) model used to measure the relative efficiencies of a group of decision making units (DMUs) are limited to either input or output orientation, anew DEA model which is both input- and output-oriented is proposed in this paper. This model can be treated as a multi-objective programming problem and solved by fuzzy-sets theory. The basic idea is to describe the efficient frontier with fuzzy observation and determine projections for DMUs on the frontier by using. the fuzzy optimization approach. The measurement of efficiencies for DMUs in this case is obtained by comparing the inputs and outputs of DMUs with their projections.