Over the past several years, substantial research effort has gone into measuring the efficiency of financial institutions. Many studies have found that inefficiencies are quite large, on the order of 20% or more of total banking industry costs and about half of the industry's potential profits. There is no consensus on the sources of the differences in measured efficiency. this paper examines several possible sources, including differences in efficiency concept, measurement method, and a number of bank, market, and regulatory characteristics. We review the existing literature and provide new evidence using data on US banks over the period 1990–1995.

This paper addresses a little examined intersection between the problem loan literature and the bank efficiency literature. We employ Granger-causality techniques to test four hypotheses regarding the relationships among loan quality, cost efficiency, and bank capital. The data suggest that problem loans precede reductions in measured cost efficiency; that measured cost efficiency precedes reductions in problem loans; and the reductions in capital at thinly capitalized banks precede increases in problem loans. Hence, cost efficiency may be an important indicator of future problem loans and problem banks. Our results are ambiguous concerning whether or not researchers should control for problem loans in efficiency estimation.