A note on quality choice, monopoly, and network externality

Introducing network externalities into a model of vertically differentiated products, Lambertini and Orsini (2001, 2003) analyze the implications of a monopolist's quality choice for social optimum. Moreover, they examine how the network externality affects quality, quantity, price, and social surplus. In this note, by looking at the nature of cost functions and the degree of network externalities, we reconsider their results, at least some of which depend upon the specificity of the cost functions. © Springer Science+Business Media, LLC 2007.