Dynamic DEA: A relative efficiency measure of decision making units

Dynamic data envelopment analysis (DDEA) is an approach which deals with assessing performance a group of DMUs (decision making units) during several periods of time. Actually, what discriminates between DDEA and other existing techniques depending on time factor such as Window analysis and the Malmquist index, is the attention to carry-over or investment activities and actually one of the most important feature of DDEA is this fact. This paper develops some assumptions into DDEA which can give managers new insights into what does happen to those investments during periods of an assessment window and how they will be effective in the future. In continue, some factors that affect on those investments within different periods are studied. Consequently, using the new insight we develop the maximum dynamic relative efficiency measure (DRE) of a DMU under evaluation over whole periods of an assessment window.