common weights determination in data envelopment analysis

in models of data envelopment analysis (dea), an optimal set of weights is generally assumed to represent the assessed decision making unit(dmu) in the best light in comparison to all the other dmus, and so there is an optimal set of weights corresponding to each dmu. the present paper, proposes a three stage method to determine one common set of weights for decision making units. then, we use these weights to rank efficient units. we demonstrate the approach by applying it to rank gas companies.