Party activists face a coordination problem: a critical mass (a barrier to coordination) must advocate a single policy alternative if the party is to succeed. The need for direction is the degree to which the merits of the alternatives respond to the underlying mood of the party. An individual's...

Firms selling multiple quality-differentiated products frequently alter their product lines when a competitor enters the market. We present a model of multiproduct monopoly and duopoly using a general "upgrades" approach that yields a powerful analytical framework. We provide an explanation for...

We propose a framework for analyzing transformations of demand. Such transformations frequently stem from changes in the dispersion of consumers' valuations, which lead to rotations of the demand curve. In many settings, profits are a U-shaped function of dispersion. High dispersion is...

A simple model of open source software (as typified by the GNU-Linux operating system) is presented. Individual user-programmers decide whether to invest their own effort to develop a software enhancement that will become a public good if so developed. The effect of changing the population size...