The conventional data envelopment analysis models deal with dualrole factor as non-discretionary (uncontrollable) factor. However, there might be dual-role factor which is under control of decision-maker. In addition, despite the fact that there are several publications addressing dual-role factors, it seems that their idea of classifying a factor as an input or an output within a single model has a limitation. They also do not consider non-zero input and output slacks and cannot fully measure the inefficiency of decision-making units. To resolve these limitations and to consider dual-role factor as well, this paper proposes a slacks-based measure model which does not consider dualrole factor as a non-discretionary factor. To compare the results of proposed approach with conventional model, a statistical analysis is run. A numerical example demonstrates the application of the proposed method. Copyright 2012 Inderscience Enterprises Ltd.