A Note on the Efficiency Characterizations Obtained in Different DEA (data Envelopment Analysis) Models

Abstract : DEA's (Data Envelopment Analysis) first formulated model was a non- linear ratio (or fractional) programming problem, as reported in Charnes, Cooper and Rhodes where it was also shown that the fractional programming transformation first given in Charnes and Cooper could be used to obtain a corresponding dual pair of linear programming problems for use in evaluating the efficiency of not-for-profit entities-such as schools, hospitals and government (including military) agencies. These formulations were to be used to secure efficiency evaluations from observed data on the multiple outputs and multiple inputs generated by the activities of the entities to be studied. Numerical evaluations with operational significance were to be secured without requiring recourse to a priori weights (or other transformations) and without requiring explicit specification of parametric functional forms for the relations that might obtain between the inputs and the outputs. Specification was to be required only for the outputs and the inputs to be considered and the DMUs (Decision Making Units) which are responsible for converting inputs into outputs and whose convex or conical combinations constitute the relevant set for obtaining the relative efficiency evaluations that are wanted.