MARKET STRUCTURE AND CONDUCT: GENERALIZED INDUSTRY PERFORMANCE GRADIENT INDEXES FOR OLIGOPOLY MARKETS

This paper generalizes Dansby-Willig's industry performance gradient index so as to explicitly relate the maximal feasible welfare improvement rate in imperfectly competitive markets with the number of firms perceiving market power and the industry-wide distribu tionof marginal costs. Two specific examples of the proposed generalized index are fully explored to obtain two results: (i) the greater number of oligopolistically behaving firms lowers but (ii) the greater variance of the marginal-cost distribution over the industry increases the maximal feasible rate of welfare improvement.