（1）The characteristics of the core competitiveness of enterprises
Banks are special enterprises.People overseas started to study the competitiveness of commercial banks from the research on that of enterprises.C.K. Prahalad and Armand Hamer(1990) are the representatives of people who study core competitiveness from the new aspect of technology and product innovation.They think that the accumulation process of core competitiveness of enterprises is accompanied by the development process of core products and technology of enterprises,which is the specific advantage accumulated by enterprises' investment and learning behaviors.Dorothy Leonard-Barton thinks that the core competitiveness is a knowledge system which can make the enterprise unique and bring it advantages of competition,which reflects on four aspects,knowledge base, technology system, management system and value system,the interaction of which is strong.Coombs（1993）thinks that the core conpetitiveness of enterprises includes the technology competitiveness of the enterprise and the organization competitiveness of combining the technology competitiveness effectively.
(2)The relationship between bank size and competitiveness
Alhadeff（1954） analyzed the Related data of the cost and produce of Clifornia from 1938 to 1950.The result showed that there is an effect of output increasing and cost decreasing in the banking in California.Big banks had an advantage over small ones in both cost and output.Beston（1965,1972）found that whatever sizes are,if other restrict condition didn't change and the bank's size doubled,the average cost would decrease by 5% to 8%,which meaned that the significant effect of economy of scale existed in all banks in statistics.
(3)The relationship between business scale and competitiveness of banks
Kolar（1987） divided the 600 banks in America into four groups in terms of their business types and examined the hypothesis of business scale efficiency one by one.The result showed that with the premise of concerning and sharing information resources business,combined business had a lower cost than single business-----there was business scale efficiency in banking.The example analyses of Berger&Humhrey（1994）showed that the scale efficiency was very small in banking,and profits weren't affected by the diversity of products,so the products through the diversity of products only can lower the cost by 5% at most.
(4)The factors affecting bank efficiency
Berger and Mester（1997）found in their research that bank efficiency was affected by many factors,such as the concept of efficiency,the measuring methods,the sample choosing,the asset sizes and the organization forms.However,in terms of the efficiency's ineracting directions and results,some affecting factors were definite,while some were different by the different research results.Lozano-Vivas（2000）calculated cost efficiency of the Spainish banks and the French banks in his research,the result was different in case of not taking environment variables into account or taking it.In former case,Spanish banks had a lower cost than French banks,while in latter case,there was almost no difference.It showed that to adapt marketing competition,commercial banks should change their own structures in time to adapt the change of environmental factors,such as population density, demand intensity and per capita income.