In this paper, a new method for centralized resource allocation based on the proposed SBM model of data envelopment analysis has been introduced. Models of DEA search targets separately for each DMU, but in this proposed model, by solving one model searches targets for all DMUs and projects all of them on the efficient frontier where this method will find a better image point rather than the previous methods. The goal is to reduce inputs and increase outputs to the non-radial. Finally, it is compared with previous methods by illustrating some examples and it seems that this method is for better. Manuscript profile

This paper aims at examining congestion in two-stage decision making units. Providing an example, it will be proved that presence or absence of congestion in the whole process of a two-stage decision making unit has nothing to do with presence or absence of it in each of stages. In other words, it is likely that the first stage to be weak efficient and the second one will have congestion, while the whole process lacks congestion. It is also possible that each stage has congestion, but it doesn’t mean that the whole process should have congestion. Then, to identify congestion in two-stage decision making units, modified Cooper model is developed. Manuscript profile

One of the important issues discussed in DEA literature is ranking efficient units. This paper presents a new method based on slack based measure SBM with free variables in sign for ranking efficient units. The new method also can rank the efficient units non-extreme. It also does not have the problem of instability and infeasibility. The proposed model specifies the largest MPSS and after that other unit’s portraits to this unit. Then, using examples will be compared with the approaches. Manuscript profile