An insight into the size efficiency of a UK bank branch network

Outlines previous research on the efficiency of financial institutions and builds on an earlier study of the relative efficiency of 190 UK bank branches by the authors to determine their size efficiency relationship and their determinants of relative inefficiency. Explains the data envelopment (DEA) method used, the data set and the input/output configuration; and summarizes the results of the previous study. Shows that size is related to efficiency and suggests that the pattern is an asymmetric U‐shaped average cost curve, with an optimum branch size of ine staff and a lending range of £3.0‐£5.25 million. Analyses the sources of scale and technical inefficiency in an individual branch and across the sample to show that diversification reduces efficiency while use of technology and management control improves it. Concludes that DEA can provide the means to raise efficiency, reduce cost income ratios and increase profitability.