In contrast to the traditional DEA approach, which is radial and takes no account of slacks, the SBM model is a non-radial, non-oriented model that deals directly with the input and output slacks of the DMU of interest. The non-radial feature acknowledges the generally non-proportional nature of noticeable deterioration in performance in the real world. The efficiency measure of the SBM model is between 0 and 1