تبعیض قیمت و انگیزه های سرمایه گذاری

We examine a model of a monopolist selling to two segments of consumers with different preferences for quality. We show that if the firm is unable to price discriminate between the segments, then there is less investment in quality. We find that both consumer segments, and society overall, may suffer if the firm is unable to price discriminate. We extend the model to duopoly competition, and find that our results still hold.

The effect of price discrimination on social welfare has been a topic of interest among economists for a long time, at least since Pigou (1920), who conjectured that price discrimination decreases welfare if the total output decreases at the same time. In 1936, the Robinson–Patman Act was passed to disallow price discrimination in the intermediary markets in the United States, and price discrimination between consumers is routinely a source of public relations problems for companies. The central question we ask is how the ability to price discriminate affects a firm's incentives to invest in quality and, in turn, how this affects consumer and social welfare. We are concerned with markets where different segments of consumers have different valuations for product quality. Business travelers care much more about their flight landing on time than do leisure travelers on the same flight going for a week-long vacation with no particular plans. A sick patient who might have a tumor cares much more than a healthy person about the kind of MRI machine his hospital has. Hospitals and welders care about oxygen quality much more than oxygen-bar owners, and a business owner cares much more about her hard drive not failing than does a consumer with nothing irreplaceable on that hard drive. In such markets, firms must make both pricing decisions and investment decisions for quality, and their incentives to invest depend critically on whether they are allowed to price discriminate between the two segments. We study a model of a monopolist supplier choosing both quality and prices. The firm operates in a market where consumers have different preferences for quality. There are two segments: discerning consumers who care about quality and undiscerning ones who do not. We examine the firm's choices under two regimes: one in which the firm is allowed to price discriminate and another in which it is not. It turns out that the supplier invests less in quality when it cannot price discriminate between the two segments. We find that the undiscerning segment that does not care about quality always suffers if price discrimination is not allowed, and that the discerning segment that cares about quality may also suffer. It turns out that if the investment cost function is not too convex, all consumers are worse off in a regime without price discrimination. Our results also hold if the markets differ in another way: the consumers value quality similarly, but have different price elasticities.1 The driving force is that consumers have different relative valuations for quality. We extend our model to a duopoly setting (with differentiated Bertrand competition), and find that our results continue to hold with strategic competition. We can interpret our model as being an upstream supplier (or an oligopoly of upstream suppliers) selling goods to almost perfectly competitive downstream retailers or intermediaries, where in some markets consumers care about the attribute, and in others they do not. Alternatively, the attribute could be something that only particular retailers care about, such as an RFID tag or particular packaging.2 In these cases, our model is a reduced-form model of vertical relations. What is the intuition behind our results? When price discrimination is allowed, the monopolist ensures that only the discerning segment pays more because of a higher investment. Without price discrimination, both segments pay for it through the uniform price. The undiscerning segment is the weak segment that gets stuck with a higher price because of the monopolist's inability to price discriminate, and this results in a lower welfare for this segment. The discerning segment is the strong segment that gets a lower price with uniform pricing.3 However, the lower price does not necessarily imply an increase in welfare. While the price is lower, investment also decreases in a regime with no price discrimination. Thus, depending on how much the investment decreases, consumers can be worse off. The magnitude of the drop in investment depends on the shape of the investment cost function.

We examine investment incentives of a firm that may or may not be able to price discriminate between two consumer segments (with one segment caring more about the investment in quality). We find that if the investment cost function is not too convex, then both consumer segments and the monopolist are worse off if price discrimination is prohibited. The unexpected result is that the discerning segment might suffer. There are two effects for this segment: Price decreases, but the investment decreases as well; and depending on the shape of the cost function, the discerning consumers may prefer to pay a higher price and get the higher-quality product. Our results suggest that price discrimination should be encouraged in certain industries, including those in which the investing firm sells to downstream firms that, in turn, sell to the final consumer. Potential empirical tests of this result crucially depend on measuring the amount of investment, investment costs, and consumers' preference for quality.