Reviews, prices and endogenous information transmission

Empirical evidence suggests that online reviews are an important source of consumers, information and a relevant determinant of the firms, revenues. Little is known, however, about how prices and reviews affect each other. This paper proposes a dynamic game to investigate this relationship. A long-lived monopoly faces a sequence of short-lived consumers whose only information about the value of an experience good is the one contained in the reviews completed by previous buyers. Neither the monopoly nor the consumers have private information about the value of the good. After buying the good, the consumers observe a quality realisation that is correlated with the actual value of the good and decide whether to complete reviews. The consumers complete reviews according to a social rule that maximises the present value of current and future consumers' utility. It is shown that a necessary condition for the existence of reviews is that the firm cannot fully appropriate the surplus generated by this increased information. Furthermore, the reviews induce a mean preserving spread on the posterior beliefs about the value of the good which, combined with the convexity with respect to the prior of the indirect utility and profit functions, implies that reviews are valuable for both the consumers and the firm. Hence, both parties are willing to face some cost in order to increase the information available in the market. The main result of the paper is that, from the firm's perspective, this cost takes the form of a ``discount'' in the price offered to current consumers.