this research identifies returns to scale (rts) of efficient decision making units (dmus) with desirable (good) and undesirable (bad) inputs and outputs by presenting a new dea (data envelopment analysis) approach. in this study, we first introduce a new input-output oriented model to determine efficient dmus in the presence of undesirable factors and then, returns to scale of these dmus are es...

introduction: awareness about the outcome of trauma patients in the emergency department (ed) has become a topic of interest. accordingly, the present study aimed to compare the rapid trauma score (rts) and worthing physiological scoring system (wpss) in predicting in-hospital mortality and poor outcome of trauma patients. methods: in this comparative study trauma patients brought to five eds i...

Return-To-Scale (RTS) is a most important topic in DEA. Many methods are not obtained for estimating RTS in DEA, yet. In this paper has developed the Banker-Trall approach to identify situation for RTS for the BCC model "multiplier form" with virtual weight restrictions that are imposed to model by DM judgments. Imposing weight restrictions to DEA models often has created problem of infeasibili...