We describe firm pricing when consumers search passively and follow simple reservation price rules. In stark contrast to other models in the literature, this approach yields equilib- rium price dispersion in pure strategies even when firms have the same marginal costs. In equilibrium, lower...

We analyze an oligopoly model with horizontal di¤erentiation and quality di¤erences. High quality goods are over-priced and under-produced. When the market is fairly covered, low quality products may be pro…table when their social contribution is negative, leading to too many products in...

Advertising messages compete for scarce attention. ?Junk? mail, ?spam? e-mail, and telemarketing calls need both parties to exert effort to generate transactions. Message recipients supply attention depending on average message beneÞt. Senders are motivated by proÞts. Costlier message...

We revisit the fundamental issue of market provision of variety associated with Chamberlin, Spence, and Dixit and Stiglitz when firms sell several products. Both products and firms are envisaged as di?erentiated. We propose a nested demand model where consumers decide upon a firm then which...

We introduce a framework that has known models of oligopolistic competition with differentiated products (the circle and the constant elasticity of substitution (CES)) as limit cases. This integrative approach incorporates both localized and global competition, as well as price-sensitive...

We consider dynamic congestion in an urban setting where trip origins are spatially distributed. All travelers must pass through a downtown bottleneck in order to reach their destination in the CBD. Each traveler chooses departure time to maximize general concave scheduling utility. We find...

We formulate a family of direct utility functions for the consumption of a differentiated good. This is used to generate a family of demand systems with flexible substitution patterns. Demand models for market shares can be estimated by regression enabling the use of instrumental variables....

We consider commuting in a congested urban area. While an efficient time-varying toll may eliminate queuing, a toll may not be politically feasible. We study the benefit of a substitute: a parking fee at the workplace. An optimal time-varying parking fee is charged at zero rate when there is...

Limited consumer attention limits product market competition: prices are stochastically lower the more attention is paid. Ads compete to be the lowest price with other ads from the same sector and they compete for attention with ads from other sectors: equilibrium sector ad shares under free...

We consider a market in which a public firm competes against private firms, and ask what happens when the public firm is privatized. In the short run, privatization is harmful because all prices rise; the disciplinary role of the public firm is lost. In the long run, privatization leads to...