Malmquist productivity index using the concept of loyalty factor in bank branches

In this study, we introduce a new concept as loyalty factor of bank branches customers. Data envelopment analysis weight restrictions is used to develop a new loyalty model and define the loyalty factor. Assurance region weight restrictions are attached to basic data envelopment analysis models using some predefined loyalty codes based on services quality and in special, e-banking. This model enhances the discrimination power of decision making units. Using the proposed loyalty factor, we extend Malmquist productivity index to determine the contribution of loyalty factor changes in two time periods on the productivity changes. The presented method is implemented in a real world case study from 177 Iranian bank branches in 2018-2019 to approve its applicability. The results for both traditional and extended Malmquist index are analyzed.