A One-Model Method Based on a Relaxed Combination of Inputs for Congestion Assessment in Interval Data Envelopment Analysis

Document Type: Research Paper


Department of Mathematics, Khorramabad branch, Islamic Azad University, Khorramabad, Iran


It is of special importance to calculate and recognize the quantity of congestion, as one of the major sources of inefficiency in different areas, and attempt to resolve it in order for reducing the costs and increasing the output. To date, various methods have been proposed for the calculation of congestion in classic data envelopment analysis (DEA) with precise input and output values while, in the real world, the input and output values are imprecise in most of the cases. The present paper proposes a new model for calculating the congestion interval for interval data in such cases that the interval inputs are not constrained to the selection of dominant projection points and, thereby, more outputs can be generated for the projection points. The proposed method is used for assessing the inefficiency and finding the values of congestion in the inputs of 20 bank branches.