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The Scientific World Journal
Volume 2014, Article ID 427673, 8 pages
Research Article

Estimation of Congestion in Free Disposal Hull Models Using Data Envelopment Analysis

Department of Mathematics, Islamic Azad University, Science and Research Branch, Tehran 1477893855, Iran

Received 21 May 2014; Revised 14 July 2014; Accepted 20 July 2014; Published 15 October 2014

Academic Editor: Mohammad Khodabakhshi

Copyright © 2014 M. Abbasi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper deals with evaluating congestion in free disposal hull (FDH) models. There are several approaches in data envelopment analysis (DEA) literatures which discuss the theory and application of congestion. However, almost all of these approaches considered convex DEA technologies. So, in the case of nonconvex technologies, including FDH technology, this field is almost nil. This paper makes an attempt to fill in this void. To do so, this study provides a pairwise comparisons-based algorithm to evaluate congestion in FDH model. This algorithm identifies the sources of congestion and estimates its amounts. It is also capable of detecting the losses amounts of output due to congestion. The validity of the proposed model is demonstrated using some numerical and empirical examples.