TY - JOUR T1 - Entry and Exit of Firms and Assessing Barriers to Entry in the Industry Sector TT - ورود و خروج بنگاه‌ها و ارزیابی شدت مانع ورود در بخش صنعت بر اساس نظریه صنعت JF - IJNAA JO - IJNAA VL - 25 IS - 82 UR - http://qjerp.ir/article-1-1873-en.html Y1 - 2017 SP - 79 EP - 110 KW - : Barrier to Entry KW - Market structure KW - Ratio of cost disadvantages KW - Net Entry N2 - Free entry and exit can increase the competition into a market. According to economic theories, it is expected that with increasing the entry barrier and decreasing the number of firms in the market, the monopoly degree increases in industrial markets. One of the structural components in the market is the entry barrier. The reason for the importance of entry barrier issue is that the existence of a barrier to entry (and also reactions of the existing firms into the market) can prevent from entering the new entrant in the market and leads the structure of the market to converge to monopoly. In this paper, in order to evaluate the entry barrier in Iranian industry sectors, we calculate Cost Disadvantage Ratio (CDR) index and the net entry rate. Moreover, this paper investigates effective factors on the net entry. The findings indicate the CDR index in the two-digit ISIC code industries is less than 1. The net entry rate is also negative in most of the industries, which imply a high barrier to entry in the industry. Results show the intensity of concentration, advertising intensity, research and development costs, returns and economies of scale also have significant and negative effects on net entry rate in Iranian industrial markets. M3 ER -