Stability and Constancy of Efficiency Level in Iranian Commercial Banks: DEA Window Analysis

Document Type : Research Article (Original Article)


1 PhD candidate of Financial Economics, Faculty of Economics and Management, Universiti Putra Malaysia, Seri Kembangan, Malaysia.

2 Associate Professor, Faculty of Administrative Sciences and Economics. University of Isfahan, Isfahan, Iran.


Evaluation of bank system performance in long term, optimum scale activity and stability of efficiency can be important subjects for bank managements and supervisory buddies for planning activates. This paper have investigated efficiency level of commercial banks of Iran by employing Data Analysis under constant and variable returns to scale and input oriented model in time period of 1991-2006. Input variables were labor force, fixed assets, bank deposits and ratio of branch number over number of Automatic Teller Machines (ATM). The credit facilities, investments and gross profit were output variables for bank activity in intermediary model.
Based on research findings, Melli bank and Refah Kargaran bank were more efficient than the others in both constant and variable returns to scale and better performance in allocation of production inputs and outputs. In the conditions of variable returns to scale, bank efficiency wasn't stable and consistent over the time. The pure technical efficiency has been increased by increasing in total assets but scale of activity was not optimum.
Commercial banks have activated under increasing return to scale and for achieving higher level of efficiency, the banks could upgrade scale of their activities. Also, there is significant relationship between the ratio of branches over ATM and technical efficiency. In other words, by increasing utilization of ATM in banks could lead to improve bank performance.