Classical Data Envelopment Analysis (DEA) models consider each Decision Making Unit (DMU), whose relative efficiency they evaluate, as a "black box", i.e., its internal structure is disregarded. The paper presents a comprehensive framework of the most advanced theoretical findings in DEA when the internal structure of the. DMUs is taken into account, thus giving directions for novel applications of such methodology and introducing it as a powerful toot for complex processes performance evaluation.
