In 2008, Chansarn (2008) conducted a study on the efficiency of 13 Thai
commercial banks from 2003 to 2006 using Data Envelopment Analysis
technique. This research investigated the performance of Thai commercial banks
in both operation and intermediation approaches. This research had shown that
Thai commercial banks were more efficient in operation approach than
intermediation approach during 2003 to 2006. Moreover, while large, medium and
small banks were all efficient in operation approach, this research also discovered
that small banks were most efficient in intermediation approach.