Multi-Period Efficiency Analysis with Flexible Measures: Oriented and Non-Oriented Approaches

In traditional data envelopment analysis (DEA) models, the relative efficiency of decision making units (DMUs) is usually evaluated in a particular period of time such that the status of each measure from the input or output viewpoint is certain. However, in many applications, the performance of organizations should be measured over multiple periods of time while the status of some factors called “flexible measures” from the perspective of input or output is uncertain. The purpose of this study is to propose approaches to evaluate the efficiency of the multi-period systems where flexible measures are presented. For this reason, oriented and non-oriented DEA-based approaches from the standpoints of individual DMU and aggregate efficiencies are rendered to measure the overall and period efficiency of multi-period systems with flexible measures. Also, efficiency changes between two periods are estimated using the Malmquist productivity index (MPI). A dataset is provided to validate the proposed approach.