2.
2.6 Definitions of Barriers  Many definitions of entry barriers have been proposed by economists over the years. The most well-known are listed below in chronological order. 1. Bain: The debate on how to define barriers to entry began almost 50 years ago when Joe Bain published his book Barriers to New Competition. In this way, it defines an entry barrier as anything that allows incumbents to earn above normal profits without attracting entry; more specifically, he argued that an entry barrier is an advantage of incumbents over potential entrants that can be measured by the extent to which incumbents can persistently keep their prices above competitive levels without attracting new businesses to the market.  Economies of scale and product diversification, which appears to be positively related to high profits (OECD, 2005). Carlton argues that the inability of Bain's input analysis is not his definition, but his failure to present a consistent theory showing that factors calculated as entry barriers lead to hyper-competitive prices. Bain's analysis, says Carlton, is based on a belief that barriers determine the number of businesses in a market that determines market competitiveness and thus participants' rates of return. This view has proven to be very simple. The number of companies in a market is determined by their ability to make profits, which depends on many factors and not just structurally, as Bain (OECD, 2005) believed.    Stigler. Twelve years after the appearance of Bain's book, George Stigler presented a very different way; instead of setting barriers to entry in terms of their outcome, he argued that the obstacles are the costs that should be borne by new entrants but not borne by incumbents. According to Stigler's definition, economies of scale cannot constitute barriers to entry, provided those new entrants have equal access to technology, because the incumbents probably faced the same economies, the issue of barriers to entry often appears not because the barriers themselves are said to be harmful, but because the competitive environment creates these conditions.  In the event of a merger, for example, the county's typical concern with entry barriers is whether they are high enough to prevent or discourage new companies from entering the market and whether the merger leads to a significant price increase. The concern usually is not whether regulators should issue a decision as this will remove an entry barrier. This point becomes even clearer, if someone imagines a market, one of the most important obstacles, is a law that protects public health by imposing specific safety and requirements on sellers. A court is unlikely to annul this law in a tender case, but the court must take this law into account when determining how difficult it will be to enter, in some cases, which could be described as an entry barrier under consideration (OECD, 2005). Therefore, it is not useful to limit the perception of barriers to entry into the conduct or characteristics of the market and that, in themselves, they justify intervention. The concept of 'barriers to entry' is not necessary for competition policy. In a 2004 article, Carlton advised that: "Instead of focusing on whether there is an entry barrier to new businesses according to some economists, analysts should explain how the industry will behave in the coming years.  Posner agreed with this view, having noted in 2002 that the important practical issue is not whether something is or is not an obstacle, but whether it will delay the new entry. In other words, it considered as a critical factor the time it would take the company to integrate into the industry and if it finally succeeded (OECD, 2005).
Bain: Barriers to New Competition.  Carlton: The inability of Bain's input analysis is not his definition, but his failure to present a consistent theory showing that factors calculated as barriers lead to hyper-competitive prices. Stigler: The obstacles are the costs that should be borne by new entrants but not borne by incumbents. Posner: The important practical issue is not whether something is or is not an entry barrier, but whether it will delay the new entry.