Third-Degree Price Discrimination Revisited

This paper solves a simple model of third-degree price discrimination assuming two independent linear demands and discusses the effects of price discrimination on monopoly profit, consumer surplus, and social welfare. In addition, using a simple model, this paper shows that the probability that price discrimination raises social welfare increases as the preferences or incomes of consumer groups become more heterogeneous. The virtual aggregated demand curve of the price-discriminating monopoly, corresponding to its aggregated marginal revenue curve, is derived. The curve is non-linear and lies above the aggregated demand curve of simple monopoly. The results of this paper may be used to explain to students the effects of third-degree price discrimination on market outcomes