Study of the firms size effect on their efficiency based on DEA approach

Investors and creditors expect that the performance of the firms, which they invested in them, proceed according to their expected conditions and their performance evaluation of the firms based on their type and size. Because of owners and shareholders multiplicity, direct monitoring on firm performance is not possible by shareholders, but this group can only receive benefit from performance evaluation from the firm. Therefore it is logical that by creating firm evaluation mechanisms they are up to maintane their benefit. This research studies the effect of firm size on its efficiency in the firms of Tehran Stock Exchange during 2007 to 2011 with the sample of 75 firms. For this purpose, the Data Envelopment Analysis technique has been used as the firms efficiency evaluation criteria and the amount of firm sale determined as the firm size. The results revealed a significant inverse relationship between efficiency and the size of firm.