The existing DEA model used to evaluate the relative efficiency of system with independent subsystems assumes that there exists no returns to scale, and one can't obtain pure technique efficiency by using this model. In this paper, C~2GS~2-ISS model that allows decision-making units to exhibit variable returns to scale is introduced. This model can be used to evaluate the pure technique efficiency of decision-making units. Efficiency of every decision-making unit is divided into pure technique efficien...