EFFECTS OF EXCLUDING THE COLUMN BEING SCORED FROM THE DEA ENVELOPMENTLP TECHNOLOGY MATRIX

The reformulation of the envelopment linear programs in DEA to score a decision making unit (DMU) by excluding the corresponding column from the technology matrix raises several theoretical and computational qu estions. This idea appears natural and has been proposed before, but o nly recently has it appeared in published form. Several issues associa ted with this modification to standard DEA analysis remain to be forma lly and comprehensively explored. One is the feasibility of the result ant LPs which, as it turns out, is not guaranteed under this modificat ion in some of the DEA models. Therefore, the status of the DMU for wh ich the LP is infeasible needs to be resolved. Other issues include th e formal equivalence relation between the modified and standard formul ations; the impact on the problem of pervasive degeneracy in the LPs a nd the interpretation of the optimal solutions. This paper investigate s these issues and others so as to provide both a firm theoretical bas is for the proposed modification in all four convexified free-disposab ility DEA models and a thorough analysis of the associated effects.