Primal (CCR) model

The primal model allows the DMU being measured to determine the set of optimal weights for each of its factors (outputs are denoted by y. and inputs by x in the following model) so as to maximise its efficiency. The solution consists of a set of weights (for outputs and y for inputs) chosen so that the efficiency of any other unit with these weights won’t exceed 1, the value at which a unit is relatively efficient. Which model is denoted primal and which dual is arbitrary, some authors prefer to call this model the primal model, as it conveys better the basic idea behind DEA. The convention followed here is the same as that used by the developers in their original paper, Chames et al (1978).