Data envelopment analysis-like models for efficiency evaluations of specialized and interdependent units

The problem of evaluating the efficiency of a set of specialized and interdependent decision making subunits (DMSUs) that make up a large decision making unit (DMU) is considered. The DMSUs are interdependent, in the sense that part of the output produced by each of them may be used as an input by the other ones. They are also specialized, hence non-homogeneous, as they may have not the same inputs and outputs. For this problem, some efficiency indexes are introduced, and they are shown to satisfy some basic properties.