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Perfect competition

A perfectly competitive market is a hypothetical market where competition is at its greatest possible level.  Neo-classical economists argued that perfect competition would produce the best possible outcomes for consumers, and society.


Key characteristics

Perfectly competitive markets exhibit the following characteristics:

  1. There is perfect knowledge, with no information failure or time lags.  Knowledge is freely available to all participants, which means that risk-taking is minimal and the role of the entrepreneur is limited.

  2. There are no barriers to entry into or exit out of the market.

  3. Firms produce homogeneous, identical, units of output that are not branded.

  4. Each unit of input, such as units of labour, are also homogeneous.

  5. No single firm can influence the market price, or market conditions. The single firm is said to be a price taker, taking its price from the whole industry.

  6. There are a very large numbers of firms in the market.

  7. There is no need for government regulation, except to make markets more competitive.

  8. There are assumed to be no externalities, that is no external costs or benefits.

  9. Firms can only make normal profits in the long run, but they can make abnormal profits in the short run.


The firm as price taker

The single firm takes its price from the industry, and is, consequently, referred to as a price taker. The industry is composed of all firms in the industry and the market price is where market demand is equal to market supply. Each single firm must charge this price and cannot diverge from it.

Perfect competition

Equilibrium in perfect competition

In the short run

Under perfect competition, firms can make super-normal profits or losses.

Perfect competition in the short run

In the long run

However, in the long run firms are attracted into the industry if the incumbent firms are making supernormal profits. This is because there are no barriers to entry and because there is perfect knowledge. The effect of this entry into the industry is to shift the industry supply curve to the right, which drives down price until the point where all super-normal profits are exhausted.  If firms are making losses, they will leave the market as there are no exit barriers, and this will shift the industry supply to the left, which raises price and enables those left in the market to derive normal profits.

Perfect competition in the long run

The super-normal profit derived by the firm in the short run acts as an incentive for new firms to enter the market, which increases industry supply and market price falls for all firms until only normal profit is made.


The benefits

It can be argued that perfect competition will yield the following benefits:

  1. Because there is perfect knowledge, there is no information failure and knowledge is shared evenly between all participants.

  2. There are no barriers to entry, so existing firms cannot derive any monopoly power.

  3. Only normal profits made, so producers just cover their opportunity cost.

  4. There is no need to spend money on advertising, because there is perfect knowledge and firms can sell all they can produce. In addition, selling unbranded goods makes it hard to construct an effective advertising campaign.

  5. There is maximum possible:

  6. There is maximum allocative and productive efficiency:

    • Equilibrium will occur where P = MC, hence allocative efficiency.

    • In the long run equilibrium will occur at output where MC = ATC, which is productive efficiency.

  7. There is also maximum choice for consumers.

Perfect competition and efficiency

How realistic is the model?

Very few markets or industries in the real world are perfectly competitive. For example, how homogeneous is the output of real firms, given that even the smallest of firms working in manufacturing or services try to differentiate their product.

Although unrealistic, it is still a useful model in two respects. Firstly, many primary and commodity markets, such as coffee and tea, exhibit many of the characteristics of perfect competition, such as the number of individual producers that exist, and their inability to influence market price. Secondly, for other markets in manufacturing and services, the model is a useful yardstick by which economists and regulators can evaluate levels of competition that exist in real markets.