Returns-to-scale and Damages-to-scale in SBM model In the presence undesirable and separable data

In accordance with the global environmental conservation awareness, undesirable outputs of productions and social activities, e.g., air pollutants and hazardous wastes, are being increasingly recognized as dangerous and undesirable. Thus, development of technologies with less undesirable outputs is an important subject of concern in every area of production. In this paper, we discuss this non-separable case. In this paper, the SBM is modified so as to take non-separable and separable data into account.